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                                                                   EXHIBIT 99.4


                            INVESTOR RIGHTS AGREEMENT


                                  BY AND AMONG


                             ASPEN TECHNOLOGY, INC.


                                       AND


                          THE STOCKHOLDERS NAMED HEREIN


                               DATED       , 2003

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                                TABLE OF CONTENTS

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TABLE OF CONTENTS........................................................................i

INVESTOR RIGHTS AGREEMENT................................................................1

BACKGROUND...............................................................................1

AGREEMENT................................................................................1

1. DEFINITIONS...........................................................................1

2. REGISTRATION RIGHTS...................................................................6

   2.1.  DEMAND REGISTRATIONS............................................................6
   2.2.  INCIDENTAL REGISTRATIONS........................................................8
   2.3.  DIVIDEND REGISTRATION...........................................................9
   2.4.  SHELF REGISTRATION..............................................................9
   2.5.  REGISTRATION PROCEDURES.........................................................9
   2.6.  ALLOCATION OF EXPENSES.........................................................13
   2.7.  INDEMNIFICATION AND CONTRIBUTION...............................................13
   2.8.  OTHER MATTERS WITH RESPECT TO UNDERWRITTEN OFFERINGS...........................16
   2.9.  INFORMATION BY HOLDER..........................................................16
   2.10. "LOCK-UP" AGREEMENT; CONFIDENTIALITY OF NOTICES................................16
   2.11. TERMINATION....................................................................16

3. PREEMPTIVE RIGHTS....................................................................16

   3.1.  RIGHTS OF INVESTORS............................................................17
   3.2.  EXCLUDED TRANSACTIONS..........................................................18
   3.3.  TERMINATION....................................................................19

4. COVENANTS OF THE COMPANY.............................................................19

   4.1.  INFORMATION REQUIREMENTS.......................................................19
   4.2.  BOARD OF DIRECTORS.............................................................19
   4.3.  REPORTS UNDER SECURITIES EXCHANGE ACT OF 1934..................................20
   4.4.  REGISTRATION RIGHTS............................................................20
   4.5.  AVAILABLE COPY.................................................................21
   4.6.  TERMINATION....................................................................21

5. TRANSFER RESTRICTIONS................................................................21

   5.1.  PROHIBITION....................................................................21
   5.2.  RESTRICTIONS...................................................................21
   5.3.  LEGENDS........................................................................22
   5.4.  ACKNOWLEDGEMENT................................................................23

6. STANDSTILL AGREEMENTS................................................................23

   6.1.  RESTRICTIONS...................................................................23
   6.2.  CERTAIN PERMITTED TRANSACTIONS AND COMMUNICATIONS..............................25
   6.3.  TERMINATION....................................................................25

7. TRADING LIMITATIONS..................................................................25

   7.1.  RESTRICTIONS...................................................................25
   7.2.  TERMINATION....................................................................26

8. CONFIDENTIALITY......................................................................26
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<Table>
                                                                                     
   8.1.  RESTRICTIONS...................................................................26
   8.2.  TERMINATION....................................................................26

9. ELECTION OF SERIES D-1 DIRECTORS.....................................................26

   9.1.  INITIAL SERIES D-1 DIRECTORS...................................................26
   9.2.  DESIGNATION OF SERIES D-1 DIRECTORS............................................27
   9.3.  COVENANT REGARDING COMMON DIRECTORS............................................26
   9.4.  TERMINATION....................................................................27

10.      NONPUBLIC INFORMATION..........................................................27

11.      GENERAL........................................................................27

   11.1. OWNERSHIP CALCULATIONS.........................................................27
   11.2. NOTICES........................................................................28
   11.3. AMENDMENTS AND WAIVERS.........................................................28
   11.4. GOVERNING LAW; VENUE; WAIVER OF JURY TRIAL.....................................29
   11.5. COUNTERPARTS; FACSIMILE SIGNATURES.............................................29
   11.6. ENTIRE AGREEMENT...............................................................29
   11.7. INTERPRETATION AND RULES OF CONSTRUCTION.......................................29
   11.8. SEVERABILITY...................................................................29
   11.9. SPECIFIC PERFORMANCE...........................................................29
</Table>

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                            INVESTOR RIGHTS AGREEMENT

     THIS AGREEMENT dated as of       , 2003 is entered into by and among Aspen
Technology, Inc., a Delaware corporation (the "Company"), and the entities
listed on the signature pages hereto (the "Investors").

                                   BACKGROUND

     A.     The Company and certain of the Investors have entered into a
Securities Purchase Agreement dated as of June 1, 2003, pursuant to which
such Investors are acquiring shares of Series D Convertible Preferred Stock
of the Company contemporaneously with the execution and delivery of this
Agreement.

     B.     Under Sections 7.01(m) and 7.02(i) of such Purchase Agreement,
the delivery of this Agreement is a condition to certain Investors'
acquisition, and the Company's sale, of such shares of Series D Convertible
Preferred Stock.

                                    AGREEMENT

     NOW, THEREFORE, in consideration of the mutual covenants and agreements set
forth herein, the parties hereto agree as follows:

     1.     DEFINITIONS. As used in this Agreement, the following terms shall
have the indicated meanings:

            "ACCREDITED INVESTOR" means each Investor that is an "accredited
     investor" within the meaning of Rule 501(a) under the Securities Act.

            "ADVENT" means Advent International Corporation, a Delaware
     corporation.

            "ADVERSE DISCLOSURE" means public disclosure of material non-public
     information, which disclosure in the good faith judgment of the Board of
     Directors of the Company (after consultation with external legal counsel)
     (i) would be required to be made in any Registration Statement so that such
     Registration Statement would not be materially misleading, (ii) would not
     be required to be made at such time but for the filing, effectiveness or
     continued use of such Registration Statement, and (iii) would be materially
     detrimental to the Company's ability to effect a material proposed merger,
     acquisition or sale.

            "AFFILIATE" of a Person shall mean any Person which, directly or
     indirectly, controls, is controlled by, or is under common control with
     such Person. The term "control" (including, with correlative meaning, the
     terms "controlled by" and "under common control with"), as used with
     respect to any Person, shall mean the possession, directly or indirectly,
     of the power to elect a majority of the board of directors (or other
     governing body) or to direct or cause the direction of the management and
     policies of such Person, whether through the ownership of voting
     securities, by contract or otherwise and, in any event and without limiting
     the generality of the foregoing, any Person owning more than 10% of the
     voting securities of another Person shall be deemed to control that Person.
     With respect to each of the initial Series D-1 Investors, the term
     "Affiliate" shall also include (i) any entity in which such Series D-1
     Investor (or one of its Affiliates) is a general partner or member, (ii)
     each investor in such Series D-1 Investor, but only in connection with the
     liquidation, winding up or dissolution of the Series D-1 Investor, and only
     to the extent of such investor's pro rata share in the Series D-1 Investor
     and (iii) any investment fund managed by Advent.

            "BENEFICIALLY OWN" has the meaning set forth in Rule 13d-3 under the
     Exchange Act, and

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     "BENEFICIAL OWNERSHIP" shall have a correlative meaning.

            "COMMISSION" means the Securities and Exchange Commission or any
     other federal agency at the time administering the Securities Act or the
     Exchange Act.

            "COMMON STOCK" means the common stock, par value $.10 per share, of
     the Company, or any common stock or other securities issued in respect of
     such Common Stock, or into which such Common Stock is converted, due to
     stock splits, stock dividends or other distributions, merger,
     consolidation, reclassifications, recapitalizations or otherwise.

            "COMPANY" has the meaning ascribed to it in the introductory
     paragraph hereto.

            "COMPANY OFFER" means a written notice of any proposed issuance,
     sale or exchange of Company-Offered Securities containing the information
     specified in Section 3.1(a).

            "COMPANY-OFFER ACCEPTANCE" means a written notice from an Investor
     to the Company containing the information specified in Section 3.1(b).

            "COMPANY-OFFER AVAILABLE UNSUBSCRIBED AMOUNT" means the difference
     between the total of all of the Company-Offer Basic Amounts available for
     purchase by Accredited Investors pursuant to Section 3.1 and the
     Company-Offer Basic Amounts subscribed for pursuant to Section 3.1.

            "COMPANY-OFFER BASIC AMOUNT" means, with respect to an Accredited
     Investor, its pro rata portion of the Company-Offered Securities determined
     by multiplying the number of Company-Offered Securities by a fraction, the
     numerator of which is the aggregate number of shares of Common Stock then
     held by such Accredited Investor (giving effect to the conversion into
     Common Stock of all shares of convertible preferred stock and exercise of
     all warrants (assuming cashless exercise) then held by such Accredited
     Investor) and the denominator of which is the total number of shares of
     Common Stock then outstanding (giving effect to (i) the conversion into
     Common Stock of all outstanding shares of convertible preferred stock, (ii)
     the exercise of all outstanding options to purchase shares of Common Stock
     issued under employee stock plans of the Company, and (iii) the shares
     issuable pursuant to the cashless exercise of warrants to the extent
     included in the numerator, in the case of (i) and (ii), which have been
     approved by a majority of the Independent Directors and that are then
     convertible or exercisable at an exercise price less than the then-current
     market price of the Common Stock).

            "COMPANY-OFFER REFUSED SECURITIES" means those Company-Offered
     Securities as to which a Company-Offer Acceptance has not been given by
     Accredited Investors pursuant to Section 3.1.

            "COMPANY-OFFER UNSUBSCRIBED AMOUNT" means, with respect to an
     Accredited Investor, any additional portion of the Company-Offered
     Securities attributable to the Company-Offer Basic Amounts of other
     Accredited Investors as such Accredited Investor indicates it will purchase
     or acquire should the other Accredited Investors subscribe for less than
     their Company-Offer Basic Amounts.

            "COMPANY-OFFERED SECURITIES" means (a) any shares of Common Stock,
     (b) any other equity securities of the Company, including shares of
     preferred stock, (c) any option, warrant or other right to subscribe for,
     purchase or otherwise acquire any equity securities of the Company, or (d)
     any debt securities convertible into capital stock of the Company.

            "COMPANY SALE" means:

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            (a)    a merger, consolidation, recapitalization, reorganization or
                   other transaction in which (i) the Company is a constituent
                   party, or (ii) a Subsidiary is a constituent party and the
                   Company issues shares of its capital stock pursuant to such
                   merger or consolidation, recapitalization, reorganization or
                   other transaction except any such merger or consolidation
                   involving the Company or a Subsidiary in which the holders of
                   capital stock of the Company immediately prior to such merger
                   or consolidation continue to hold immediately following such
                   merger or consolidation more than 50% by voting power of the
                   capital stock of or ownership interest in (a) the surviving
                   or resulting entity or (b) if the surviving or resulting
                   entity is a wholly owned subsidiary of another entity
                   immediately following such merger or consolidation, the
                   parent entity of such surviving or resulting entity; or

            (b)    the sale, in a single transaction or series of related
                   transactions, (i) by the Company of all or substantially all
                   the assets of the Company (except where such sale is to a
                   wholly owned subsidiary of the Company) or (ii) by the
                   stockholders of the Company of more than 50% by voting power
                   of the then-outstanding capital stock of the Company.

            "COMPETITOR" shall mean (a) any Person (i) that itself or together
     with its Affiliates, derives any portion of its business revenues from
     developing, maintaining, supporting, marketing, licensing, selling,
     implementing, training or providing other services related to software
     products or services used in the process industries, including without
     limitation, the oil and gas, refining, petrochemical, chemical or
     pharmaceutical businesses and (ii) to which the Company is then selling or
     providing, or has previously sold or provided at any time within the past
     two (2) years, any of the products or services described in the preceding
     clause (i), and (b) with respect to Series D-1 Investors, any
     institutional investor that owns 10% or more of the publicly traded stock
     of a Person described in clause (a) above or 30% or more of the privately
     owned equity interests of a Person described in clause (a) above.

            "CONFIDENTIAL INFORMATION" means any information that is labeled as
     confidential, proprietary or secret that an Investor obtains from the
     Company pursuant to financial statements, reports and other materials
     provided by the Company to such Investor pursuant to this Agreement.

            "CONVERTIBLE DEBENTURES" means the Company's 5 1/4% Convertible
     Subordinated Debentures due June 15, 2005.

            "EXCHANGE ACT" means the Securities Exchange Act of 1934, as
     amended, and any successor thereto, and the rules and regulations
     promulgated thereunder or in connection therewith, all as the same shall be
     in effect from time to time.

            "INDEMNIFIED PERSON" means a Person entitled to indemnification
     pursuant to Section 2.6.

            "INDEMNIFYING PERSON" means a Person obligated to provide
     indemnification pursuant to Section 2.6.

            "INDEPENDENT DIRECTOR" means, as of a given time, a director of the
     Company who is eligible to serve on the Audit Committee of the Board of
     Directors of the Company under the then-applicable rules of the Securities
     and Exchange Commission and the Nasdaq National Market (or such other
     exchange, market or trading or quotation facility on which the Common Stock
     is then listed).

            "INVESTOR" means each Person listed on the signature pages hereto
     and each other Person to which Shares are Transferred pursuant to Section
     5.2(c) or (d), PROVIDED that such Person delivers in accordance with such
     Section a written instrument agreeing to be bound by the terms of this
     Agreement.

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            "OTHER REGISTRATION RIGHTS" means written agreements entered into
     after the date hereof under which the Company agrees to include securities
     of the Company (other than Registrable Shares) in a Registration Statement,
     PROVIDED that "Other Registration Rights" shall not include any such
     agreement to the extent it relates solely to securities of the Company
     issued in connection with the acquisition by the Company or any Subsidiary
     of all or a majority of the equity or assets of any entity or line of
     business.

            "OTHER REGISTRATION RIGHTS HOLDERS" means holders of securities
     subject to Other Registration Rights.

            "PERSON" means an individual or a corporation, partnership, limited
     liability company, association, trust, or any other entity or organization,
     including a government or political subdivision or an agency or
     instrumentality thereof.

            "PROSPECTUS" means the prospectus included in any Registration
     Statement, as amended or supplemented by an amendment or prospectus
     supplement, including post-effective amendments, and all material
     incorporated by reference or deemed to be incorporated by reference in such
     Prospectus.

            "PURCHASE AGREEMENT" means the Securities Purchase Agreement dated
     as of June 1, 2003 by and among the Company and the Investors.

            "REGISTRABLE SHARES" means, collectively, Series D-1 Registrable
     Shares and Series D-2 Registrable Shares.

            "REGISTRATION EXPENSES" means all expenses incurred by the Company
     in complying with the provisions of Section 2, including all registration
     and filing fees, exchange listing fees, printing expenses, fees and
     expenses of counsel for the Company and the fees and expenses of
     Registration Selling Investor Counsel, state Blue Sky fees and expenses,
     and the expense of any special audits incident to or required by any such
     registration, but excluding underwriting discounts, selling commissions and
     the fees and expenses of Registration Selling Investors' own counsel (other
     than Registration Selling Investor Counsel).

            "REGISTRATION INITIATING INVESTORS" means the Series D-1 Investors
     initiating a request for registration pursuant to Section 2.1(a).

            "REGISTRATION SELLING INVESTOR" means any Investor owning
     Registrable Shares included in a Registration Statement.

            "REGISTRATION SELLING INVESTOR COUNSEL" means (a) if Advent or one
     of its Affiliates is participating as a Registration Selling Investor with
     respect to a registration, counsel selected by Advent to represent all
     Registration Selling Investors with respect to such registration, or (b) if
     Advent or one of its Affiliates is not participating as a Registration
     Selling Investor with respect to a registration, counsel selected by the
     holders of a majority of the Registrable Shares to be included in such
     registration to represent all Registration Selling Investors with respect
     to such registration.

            "REGISTRATION STATEMENT" means a registration statement filed by the
     Company with the Commission for a public offering and sale of securities of
     the Company, other than (a) a registration statement on Form S-4 or Form
     S-8, or their successors, or any other form for a similar limited purpose,
     or (b) any registration statement covering only securities proposed to be
     issued in exchange for securities or assets of another corporation.

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            "REMAINING INVESTOR-OFFERED SHARES" has the meaning ascribed to it
     in Section 4.2(b).

            "RULE 144" means Rule 144 promulgated under the Securities Act, and
     any successor rule or regulation thereto, and in the case of any referenced
     section of such rule, any successor section thereto, collectively and as
     from time to time amended and in effect.

            "SECURITIES ACT" means the Securities Act of 1933, as amended, and
     any successor thereto, and the rules and regulations promulgated thereunder
     or in connection therewith, all as the same shall be in effect from time to
     time.

            "SERIES D CERTIFICATE" means the Certificate of Designations of
     Series D-1 Convertible Preferred Stock and Series D-2 Convertible Preferred
     Stock forming a part of the Certificate of Incorporation of the Company.

            "SERIES D-1 DIRECTORS" means the members of the Board of Directors
     of the Company elected by the holders of shares of Series D-1 Stock
     pursuant to the Series D Certificate.

            "SERIES D-1 INVESTORS" means those Investors to the extent they hold
     Series D-1 Registrable Shares, which initially shall consist of the
     entities identified on the signature pages hereto as Series D-1 Investors.

            "SERIES D-1 REGISTRABLE SHARES" means (a) the shares of Common Stock
     issued or issuable upon conversion of the Series D-1 Stock, (b) any other
     shares of Common Stock, and any shares of Common Stock issued or issuable
     upon the conversion or exercise of any other securities, acquired by the
     Series D-1 Investors pursuant to Section 3, (c) the shares of Common Stock
     issued or issuable upon the exercise of Series D-1 Warrants, and (d) any
     other shares of Common Stock issued in respect of such shares; PROVIDED,
     HOWEVER, that shares of Common Stock that are Series D-1 Registrable Shares
     shall cease to be Series D-1 Registrable Shares upon any sale pursuant to a
     Registration Statement or Rule 144 or at such time at which such Series D-1
     Registrable Shares may be sold pursuant to paragraph (k) of Rule 144.

            "SERIES D-1 STOCK" means the Series D-1 Convertible Preferred Stock
     of the Company issued pursuant to the Purchase Agreement.

            "SERIES D-1 WARRANTS" means the warrants being issued on the date
     hereof to Series D-1 Investors pursuant to the Purchase Agreement.

            "SERIES D-2 INVESTORS" means those Investors to the extent they hold
     Series D-2 Registrable Shares, which initially shall consist of the
     entities identified on the signature pages hereto as Series D-2 Investors.

            "SERIES D-2 REGISTRABLE SHARES" means (a) the shares of Common Stock
     issued or issuable upon conversion of the Series D-2 Stock, (b) any other
     shares of Common Stock, and any shares of Common Stock issued or issuable
     upon the conversion or exercise of any other securities, acquired by the
     Series D-2 Investors pursuant to Section 3, (c) the shares of Common Stock
     issued or issuable upon the exercise of the Series D-2 Warrants, and (d)
     any other shares of Common Stock issued in respect of such shares;
     PROVIDED, HOWEVER, that shares of Common Stock that are Series D-2
     Registrable Shares shall cease to be Series D-2 Registrable Shares upon any
     sale pursuant to a Registration Statement or Rule 144 or at such time as
     when such Series D-2 Registrable Shares may be sold pursuant to paragraph
     (k) of Rule 144.

            "SERIES D-2 SECURITIES" means the Series D-2 Stock and the shares of
     Common Stock issuable

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     upon conversion thereof or as payment of dividends thereon.

            "SERIES D-2 STOCK" means the Series D-2 Convertible Preferred Stock
     of the Company issued pursuant to the Series D Certificate.

            "SERIES D-2 WARRANTS" means the warrants being issued on the date
     hereof to Series D-2 Investors pursuant to the Purchase Agreement and the
     warrants issued to the Series D-2 Investors pursuant to the Repurchase and
     Exchange Agreement, dated as of June 1, 2003, by and among the Company and
     the Series D-2 Investors.

            "SHARES" means, collectively, shares of Series D-1 Stock and Series
     D-2 Stock held by the Investors.

            "SHELF REGISTRATION STATEMENT" means a Registration Statement filed
     by the Company with the Commission pursuant to Section 2.4 covering the
     resale of all Series D-2 Registrable Shares for an offering to be made on a
     continuous basis pursuant to Rule 415 promulgated under the Securities Act.

            "SUBSIDIARY" means any corporation or other entity of which the
     capital stock or other ownership interests having ordinary voting power to
     elect a majority of the board of directors or other Persons performing
     similar functions is at the time directly or indirectly owned by the
     Company.

            "TRADING DAY" means (a) any day on which the Common Stock is listed
     or quoted and traded on the Nasdaq National Market, the New York Stock
     Exchange, the American Stock Exchange or the Nasdaq SmallCap Market or (b)
     if the Common Stock is not traded on any such market, then a day on which
     trading occurs on the New York Stock Exchange (or any successor thereto).

            "TRANSFER" means, as the context requires, (a) any sale, transfer,
     distribution or other disposition, whether voluntarily or by operation of
     law, or (b) the act of effecting such a sale, transfer, distribution or
     other disposition.

     2.     REGISTRATION RIGHTS

            2.1.   DEMAND REGISTRATIONS

                   (a)    One or more Series D-1 Investors may, at any time,
            request, in writing, that the Company file a Registration Statement
            to effect the registration of an offering of Series D-1 Registrable
            Shares owned by such Series D-1 Investor(s) and having an aggregate
            value of at least $10,000,000, based on the last reported sale price
            of the Common Stock on the trading day immediately preceding the
            date of such request. If the Company files a Registration Statement
            on Form S-3 (or any successor form) pursuant to this Section 2.1(a),
            the Company shall set forth therein any information that may be
            required in a registration that is filed on Form S-1 and that the
            underwriter lead managing the offering requests be expressly
            included in the Registration Statement.

                   (b)    Upon receipt of any request for registration pursuant
            to this Section 2, the Company shall promptly (but in any event
            within five days) give written notice of such proposed registration
            to all other Series D-1 Investors. Such other Series D-1 Investors
            shall have the right, by giving written notice to the Company within
            20 days after the Company provides its notice, to elect to have
            included in such registration such of their Series D-1 Registrable
            Shares as such Series D-1 Investors may request in such notice of
            election, subject in the case of an

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            underwritten offering to the terms of Section 2.1(c). Thereupon, the
            Company shall, as expeditiously as possible, use all commercially
            reasonable efforts to effect the registration on an appropriate
            registration form of all Series D-1 Registrable Shares that the
            Company has been requested to so register.

                   (c)    If the Registration Initiating Investors intend to
            distribute the Series D-1 Registrable Shares covered by their
            request by means of an underwriting, they shall so advise the
            Company as a part of their request made pursuant to Section 2.1(a)
            and the Company shall include such information in its written notice
            referred to in Section 2.1(b). In such event, (i) the right of any
            other Series D-1 Investor to include its Series D-1 Registrable
            Shares in such registration pursuant to Section 2.1(a) shall be
            conditioned upon such other Series D-1 Investor's participation in
            such underwriting on the terms set forth herein, and (ii) all Series
            D-1 Investors including Series D-1 Registrable Shares in such
            registration shall enter into an underwriting agreement upon
            customary terms with the underwriter or underwriters managing the
            offering; PROVIDED that such underwriting agreement shall not
            provide for indemnification or contribution obligations on the part
            of the Series D-1 Investors materially greater than the obligations
            of the Series D-1 Investors pursuant to Section 2.7. The Company
            shall have the right to select the managing underwriter(s) for any
            underwritten offering requested pursuant to Section 2.1(a), which
            selection must be made out of a pool of three underwriting firms
            chosen by the Company and the Registration Initiating Investors,
            each of which firms shall have a national reputation and experience
            with software companies. If any Series D-1 Investor that has
            requested inclusion of its Series D-1 Registrable Shares in such
            registration as provided above disapproves of the terms of the
            underwriting, such Person may elect, by written notice to the
            Company, to withdraw its Series D-1 Registrable Shares from such
            Registration Statement and underwriting. If the lead managing
            underwriter advises the Company in writing that marketing factors
            require a limitation on the number of shares to be underwritten, the
            number of Series D-1 Registrable Shares to be included in the
            Registration Statement and underwriting shall be allocated among all
            Series D-1 Investors requesting registration in proportion, as
            nearly as practicable, to the respective number of Series D-1
            Registrable Shares each Series D-1 Investor has requested be
            included in such registration.

                   (d)    The Company shall not be required to effect more than
            a total of four registrations requested pursuant to Section 2.1(a).
            The Series D-1 Investors shall not deliver a notice pursuant to
            Section 2.1(a) requesting registration of any underwritten offering
            until at least 18 months after the closing of any prior underwritten
            offering registered pursuant to a request under Section 2.1(a). For
            purposes of this Section 2.1(d), a Registration Statement shall not
            be counted until such time as such Registration Statement has been
            declared effective by the Commission. If the Registration Initiating
            Investors withdraw their request for such registration, it shall not
            count as a Registration Statement if the Registration Initiating
            Investors pay the Registration Expenses therefor pursuant to Section
            2.6. Notwithstanding the foregoing, any request withdrawn by the
            Registration Initiating Investors as a result of information
            concerning the business or financial condition of the Company, where
            such information is made known to the Series D-1 Investors after the
            date on which such registration was requested, shall not count as a
            Registration Statement.

                   (e)    If at the time of any request to register Series D-1
            Registrable Shares by Registration Initiating Investors pursuant to
            this Section 2.1, the Company is engaged or has plans to engage in a
            registered public offering or is engaged in a material proposed
            acquisition, disposition, financing, reorganization,
            recapitalization or similar transaction that, in the good faith
            determination of the Company's Board of Directors, would be
            adversely affected by the requested registration, then the Company
            may at its option direct that such request be delayed

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            for a period not in excess of 30 days from the date of such request,
            such right to delay a request to be exercised by the Company not
            more than once in any 12-month period.

            2.2.   INCIDENTAL REGISTRATIONS

                   (a)    Whenever the Company proposes to file a Registration
            Statement covering shares of Common Stock (other than a Registration
            Statement filed (i) pursuant to Section 2.1, 2.3 or 2.4, (ii) in
            accordance with the requirements of a written agreement entered into
            prior to the date hereof, (iii) with respect to shares issued by the
            Company in connection with an acquisition by the Company or any
            Subsidiary of all or a majority of the equity or assets of any
            entity, or (iv) with respect to a so-called "private investment,
            public equity" (a/k/a "PIPE") offering of Company-Offered Securities
            to which the provisions of Section 3.1 apply, except in any such
            case to the extent expressly permitted therein) at any time and from
            time to time, it will, prior to such filing, give written notice to
            all Series D-1 Investors of its intention to do so; PROVIDED that no
            such notice need be given if no Series D-1 Registrable Shares are to
            be included therein as a result of a written notice from the
            managing underwriter pursuant to Section 2.2(b). Upon the written
            request of a Series D-1 Investor or Series D-1 Investors given
            within 10 days after the Company provides such notice (which request
            shall state the intended method of disposition of such Series D-1
            Registrable Shares), the Company shall use all commercially
            reasonable efforts to cause all Series D-1 Registrable Shares that
            the Company has been requested by such Series D-1 Investor or Series
            D-1 Investors to register to be registered under the Securities Act
            to the extent necessary to permit their sale or other disposition in
            accordance with the intended methods of distribution specified in
            the request of such Series D-1 Investor or Series D-1 Investors;
            PROVIDED that the Company shall have the right to postpone or
            withdraw any registration effected pursuant to this Section 2.2
            without obligation upon 10 days' advance written notice to the
            Series D-1 Investors. Upon receipt of such notice, the Series D-1
            Investors may elect to exercise their right to demand a registration
            in accordance with Section 2.1.

                   (b)    If the registration for which the Company gives notice
            pursuant to Section 2.2(a) is a registered public offering involving
            an underwriting, the Company shall so advise the Series D-1
            Investors as a part of the written notice given pursuant to Section
            2.2(a). In such event, (i) the right of any Series D-1 Investor to
            include its Series D-1 Registrable Shares in such registration
            pursuant to this Section 2.2 shall be conditioned upon such Series
            D-1 Investor's participation in such underwriting on the terms set
            forth herein and (ii) all Series D-1 Investors including Series D-1
            Registrable Shares in such registration shall enter into an
            underwriting agreement upon customary terms with the underwriter or
            underwriters selected for the underwriting by the Company. If any
            Series D-1 Investor who has requested inclusion of its Series D-1
            Registrable Shares in such registration as provided above
            disapproves of the terms of the underwriting, such Person may elect,
            by written notice to the Company, to withdraw its shares from such
            Registration Statement and underwriting. If the managing underwriter
            advises the Company in writing that marketing factors require a
            limitation on the number of shares to be underwritten, the shares
            held by holders other than the Series D-1 Investors and Other
            Registration Rights Holders shall be excluded from such Registration
            Statement and underwriting to the extent deemed advisable by the
            managing underwriter, and if a further reduction of the number of
            shares is required, the number of shares that may be included in
            such Registration Statement and underwriting shall be allocated
            among all Series D-1 Investors and Other Registration Rights Holders
            requesting registration in proportion, as nearly as practicable, to
            the respective number of shares of Common Stock (on an as converted
            basis) held by them on the date the Company gives the notice
            specified in Section 2.2(a). If any Series D-1 Investor or Other
            Registration Rights Holder would thus be entitled to include more

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            shares than such holder has requested to be registered, the excess
            shall be allocated among other requesting Series D-1 Investors and
            Other Registration Rights Holders pro rata in the manner described
            in the preceding sentence.

            2.3.   DIVIDEND REGISTRATION. For so long as it is required by the
     terms of the Series D Certificate, shares of Common Stock issued in payment
     of dividends on the Shares shall be, at the time such shares are issued,
     registered for resale for an offering to be made on a continuous basis
     pursuant to Rule 415 of the Securities Act. Whenever the Company proposes
     to file a Registration Statement covering shares of Common Stock to be
     issued in payment of dividends on Shares, it will, prior to such filing,
     give written notice to all Investors of its intention to do so. Upon
     issuance, such shares shall constitute Registrable Shares in accordance
     with the definition thereof in Section 1. The Company shall cause all such
     Registrable Shares to be registered under the Securities Act to permit
     their sale or other disposition by any methods of distribution reasonably
     requested by the Investors, other than by means of an underwriting.

            2.4.   SHELF REGISTRATION. The Company shall prepare and file with
     the Commission a Shelf Registration Statement as promptly as practicable
     after the date hereof and shall take such steps as are necessary to enable
     the Shelf Registration to be declared effective by the Commission as
     promptly as practicable after the date hereof (and in any event by no later
     than 90 days after the date of this Agreement or, if the Shelf Registration
     Statement (including any of the documents incorporated by reference
     therein) is the subject of a complete or partial review by the Commission,
     in any event by no later than 120 days after the date of this Agreement).
     The Shelf Registration Statement shall be on Form S-3 (except if the
     Company is not then eligible to register for resale the Series D-2
     Registrable Shares on Form S-3, in which case such Shelf Registration
     Statement shall be on such other form as the Company is eligible to use)
     and shall contain the "Plan of Distribution" attached hereto as ANNEX A.
     The Company shall notify each Series D-2 Investor in writing promptly (in
     any event within one Trading Day) after receiving notification from the
     Commission that the Shelf Registration Statement has been declared
     effective.

            2.5.   REGISTRATION PROCEDURES

                   (a)    If and whenever the Company is required by the
            provisions of this Agreement to use all commercially reasonable
            efforts to effect the registration of any Registrable Shares under
            the Securities Act, the Company shall:

                          (i)    prepare and file with the Commission a
                                 Registration Statement with respect to such
                                 Registrable Shares (which, in the case of the
                                 Series D-2 Registrable Shares, shall be the
                                 Shelf Registration Statement) and use all
                                 commercially reasonable efforts to cause that
                                 Registration Statement to become effective as
                                 soon as possible;

                          (ii)   not less than three Trading Days prior to the
                                 filing of a Registration Statement or any
                                 related Prospectus or any amendment or
                                 supplement thereto (including any document that
                                 would be incorporated or deemed to be
                                 incorporated therein by reference), the Company
                                 shall (i) furnish to the each Registration
                                 Selling Investor and its counsel copies of all
                                 such documents proposed to be filed, which
                                 documents (other than those incorporated or
                                 deemed to be incorporated by reference) will be
                                 subject to the review of such Registrable
                                 Selling Investor and its counsel, and (ii)
                                 cause its officers and directors, counsel and
                                 independent certified public accountants to
                                 respond to such inquiries as shall be
                                 necessary, in the reasonable opinion of
                                 respective counsel, to conduct a reasonable
                                 investigation within the meaning of the
                                 Securities Act;

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                                 and the Company shall not file any Registration
                                 Statement or any such Prospectus or any
                                 amendments or supplements thereto to which the
                                 Registrable Selling Investors holding a
                                 majority of the Registrable Securities to be
                                 registered thereunder and their counsel shall
                                 reasonably object, PROVIDED that such objection
                                 is communicated to the Company within three
                                 Trading Days of receipt of such documents;

                          (iii)  as expeditiously as possible prepare and file
                                 with the Commission any amendments and
                                 supplements to the Registration Statement and
                                 the prospectus included in the Registration
                                 Statement as may be necessary to comply with
                                 the provisions of the Securities Act (including
                                 the anti-fraud provisions thereof) and use all
                                 commercially reasonable efforts to keep the
                                 Registration Statement continuously effective:

                                 (A)    in the case of a shelf registration of
                                        an offering of Series D-1 Registrable
                                        Shares on a continuous basis under Rule
                                        415 under the Securities Act for 180
                                        days from the effective date or such
                                        lesser period until all such Registrable
                                        Shares are sold,

                                 (B)    in the case of a Registration Statement
                                        filed pursuant to Section 2.3 with
                                        respect to shares of Common Stock paid
                                        as dividends on the Shares, for (1) 45
                                        days from the date such dividends were
                                        issued, if such dividends represent no
                                        more than one year's accumulated
                                        dividends on the Shares, (2) 90 days
                                        from the date such dividends were
                                        issued, if such dividends represent more
                                        than one year's accumulated dividends on
                                        the Shares or (3) such lesser period
                                        until all such shares of Common Stock
                                        are sold,

                                 (C)    in the case of the Shelf Registration
                                        Statement filed pursuant to Section 2.4,
                                        until the earliest of (1) the second
                                        anniversary of the date hereof, (2) the
                                        date on which all of the Series D-2
                                        Registrable Shares covered by the Shelf
                                        Registration Statement have been sold,
                                        and (3) the date on which all of such
                                        Series D-2 Registrable Shares may be
                                        sold pursuant to paragraph (k) of Rule
                                        144 (assuming utilization of any
                                        cashless exercise feature of any
                                        securities), as determined by the
                                        Company after consultation with legal
                                        counsel; PROVIDED that if the Company
                                        ceases to keep the Registration
                                        Statement effective by reason of Section
                                        2.5(a)(iii)(C)(3), the Company must
                                        certify to the Series D-2 Investors that
                                        the Series D-2 Registrable Shares may be
                                        sold pursuant to paragraph (k) of Rule
                                        144 (assuming utilization of any
                                        cashless exercise feature of any
                                        securities), and

                                 (D)    in the case of all other registrations,
                                        for (1) 45 days from the effective date
                                        or such greater period, up to 120 days,
                                        as an underwriter may require, or (2)
                                        such lesser period until all such
                                        Registrable Shares are sold;

                                 PROVIDED that the number of days specified in
                                 the foregoing clauses (A), (B) and (D) shall
                                 not include any day on which a Registration
                                 Selling Investor is restricted from offering or
                                 selling Registrable Shares pursuant to Section
                                 2.5(b) or 2.5(c) below.

                          (iv)   in all cases respond as promptly as reasonably
                                 possible to any comments

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                                 received from the Commission with respect to
                                 any Registration Statement or any amendment
                                 thereto and as promptly as reasonably possible
                                 provide to the counsel for the Registration
                                 Selling Investors true and complete copies of
                                 all correspondence from and to the Commission
                                 relating to the applicable Registration
                                 Statement;

                          (v)    as expeditiously as possible furnish to each
                                 Registration Selling Investor and its counsel,
                                 without charge, at least one conformed copy of
                                 the applicable Registration Statement and each
                                 amendment thereto, including financial
                                 statements and schedules, all documents
                                 incorporated or deemed to be incorporated
                                 therein by reference, and all exhibits to the
                                 extent requested by such Person (including
                                 those previously furnished or incorporated by
                                 reference) promptly after the filing of such
                                 documents with the Commission;

                          (vi)   as expeditiously as possible furnish to each
                                 Registration Selling Investor (with a copy to
                                 counsel to such Registration Selling Investors)
                                 such reasonable numbers of copies of the
                                 Prospectus, including any preliminary
                                 Prospectus, in conformity with the requirements
                                 of the Securities Act, and such other documents
                                 as such Registration Selling Investor may
                                 reasonably request in order to facilitate the
                                 public sale or other disposition of the
                                 Registrable Shares owned by such Registration
                                 Selling Investor; and the Company hereby
                                 consents to the use of any such Prospectus and
                                 each amendment or supplement thereto by each
                                 Registration Selling Investor in connection
                                 with the offering and sale of the Registrable
                                 Securities covered by such Prospectus and any
                                 amendment or supplement thereto;

                          (vii)  use all commercially reasonable efforts to
                                 avoid the issuance of or, if issued, obtain the
                                 withdrawal of (x) any order suspending the
                                 effectiveness of any Registration Statement or
                                 (y) any suspension of the qualification (or
                                 exemption from qualification) of any of the
                                 Registrable Securities for sale in any
                                 jurisdiction as soon as reasonably practicable;

                          (viii) as expeditiously as possible (and in the case
                                 of the Shelf Registration Statement, prior to
                                 the public offering of Registrable Securities
                                 pursuant thereto) use all commercially
                                 reasonable efforts to register or qualify the
                                 Registrable Shares covered by the Registration
                                 Statement under the securities or Blue Sky laws
                                 of such states as the Registration Selling
                                 Investors shall reasonably request, and do any
                                 and all other acts and things that may be
                                 necessary or desirable to enable the
                                 Registration Selling Investors to consummate
                                 the public sale or other disposition in such
                                 states of the Registrable Shares owned by the
                                 Registration Selling Investors; PROVIDED,
                                 HOWEVER, that the Company shall not be required
                                 in connection with this paragraph (viii) to
                                 qualify as a foreign corporation or execute a
                                 general consent to service of process in any
                                 jurisdiction;

                          (ix)   as expeditiously as possible, cause all such
                                 Registrable Shares to be listed on each
                                 securities exchange or automated quotation
                                 system on which similar securities issued by
                                 the Company are then listed;

                          (x)    promptly provide a transfer agent and registrar
                                 for all such Registrable Shares not later than
                                 the effective date of such registration
                                 statement;

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<Page>

                          (xi)   cooperate with the Registration Selling
                                 Investors to facilitate the timely preparation
                                 and delivery of certificates representing
                                 Registrable Securities to be delivered to a
                                 transferee pursuant to an effective
                                 Registration Statement, which certificates
                                 shall be free, to the extent permitted
                                 hereunder, of all restrictive legends, and to
                                 enable such Registrable Securities to be in
                                 such denominations and registered in such names
                                 as any such Registration Selling Investors may
                                 request;

                          (xii)  promptly make available for inspection by the
                                 Registration Selling Investors, any managing
                                 underwriter participating in any disposition
                                 pursuant to such Registration Statement, and
                                 any attorney or accountant or other agent
                                 retained by any such underwriter or selected by
                                 the Registration Selling Investors, all
                                 financial and other records, pertinent
                                 corporate documents and properties of the
                                 Company and cause the Company's officers,
                                 directors, employees and independent
                                 accountants to supply all information
                                 reasonably requested by any such seller,
                                 underwriter, attorney, accountant or agent in
                                 connection with such Registration Statement;
                                 provided that the Company will not make
                                 available to any Series D-2 Investor material
                                 nonpublic information;

                          (xiii) in connection with an underwritten disposition
                                 of Registrable Shares, provide such reasonable
                                 assistance in the marketing of the Registrable
                                 Shares as is customary of issuers in primary
                                 underwritten public offerings (including
                                 participation by its senior management in "road
                                 shows");

                          (xiv)  as expeditiously as possible, notify each
                                 Registration Selling Investor, promptly after
                                 it shall receive notice thereof, of the time
                                 when such Registration Statement has become
                                 effective or a supplement to any Prospectus
                                 forming a part of such Registration Statement
                                 has been filed; and

                          (xv)   as expeditiously as possible following the
                                 effectiveness of such Registration Statement,
                                 notify each seller of such Registrable Shares
                                 of any request by the Commission for the
                                 amending or supplementing of such Registration
                                 Statement or Prospectus.

                   (b)    At any time when a Prospectus is required to be
            delivered under the Securities Act, the Company shall promptly
            notify each Registration Selling Investor and its counsel of any of
            the following events: (i) the Commission notifies the Company
            whether there will be a "review" of the Registration Statement; (ii)
            the Commission comments in writing on the Registration Statement (in
            which case the Company shall deliver to each Registration Selling
            Investor a copy of such comments and of all written responses
            thereto); (iii) the Registration Statement or any post-effective
            amendment is declared effective; (iv) the Commission or any other
            Federal or state governmental authority requests any amendment or
            supplement to the Registration Statement or Prospectus or requests
            additional information related thereto; (v) the Commission issues
            any stop order suspending the effectiveness of the Registration
            Statement or initiates any Suit (as defined in the Purchase
            Agreement) for that purpose; (vi) the Company receives notice of any
            suspension of the qualification or exemption from qualification of
            the Registrable Securities for sale in any jurisdiction, or the
            initiation or threat of any Suit for such purpose; or (vii) the
            financial statements included in the Registration Statement become
            ineligible for inclusion therein or any statement made in the
            Registration Statement or Prospectus or any document incorporated or
            deemed to be incorporated therein by reference is untrue in any
            material respect or any revision to the Registration Statement,
            Prospectus or

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<Page>

            other document is required so that it will not contain any untrue
            statement of a material fact or omit to state any material fact
            required to be stated therein or necessary to make the statements
            therein, in light of the circumstances under which they were made,
            not misleading. If requested, the Registration Selling Investors
            shall immediately cease making offers of Registrable Shares pursuant
            to the Registration Statement until its receipt of the copies of the
            supplemented or amended Prospectus. Following receipt of the revised
            Prospectuses, the Registration Selling Investors shall be free to
            resume making offers of the Registrable Shares.

                   (c)    In the event that it is advisable to suspend use of a
            Prospectus included in a Registration Statement because continued
            use would require Adverse Disclosure, the Company shall notify all
            Registration Selling Investors to such effect, and, upon receipt of
            such notice, each such Registration Selling Investor shall
            immediately discontinue any sales of Registrable Shares pursuant to
            such Registration Statement until such Registration Selling Investor
            has received copies of a supplemented or amended Prospectus or until
            such Registration Selling Investor is advised in writing by the
            Company that the then current Prospectus may be used and has
            received copies of any additional or supplemental filings that are
            incorporated or deemed incorporated by reference in such Prospectus.
            Notwithstanding anything to the contrary herein, the Company shall
            not exercise its rights under this Section 2.5(c) to suspend sales
            of Registrable Shares for a period in excess of 30 consecutive days
            or a total of 60 days in any 365-day period, PROVIDED that the
            Company may suspend such sales for a period of up to 90 consecutive
            days (and a total of 90 days in a 365-day period) if the reason for
            the continued suspension beyond 30 days relates solely to the
            preparation of financial statements required to be filed in
            accordance with Item 7 of Form 8-K under the Exchange Act (in which
            event the Company shall use all commercially reasonable efforts to
            cause such financial statements to be prepared as promptly as
            reasonably practicable in the circumstances), and such suspension
            period shall automatically terminate two Trading Days after the
            filing of such financial statements. In no event shall the Company's
            right under this Section 2.5(c) be exercised to suspend sales of
            Registrable Shares beyond the period during which sales of
            Registrable Shares would require Adverse Disclosure. After the end
            of any suspension period under this Section 2.5, the Company shall
            use all commercially reasonable efforts (including filing any
            required supplemental prospectus) to restore, as promptly as
            reasonably possible, the effectiveness of the Registration Statement
            and the ability of the Registration Selling Investors to publicly
            resell their Registrable Securities pursuant to such effective
            Registration Statement.

            2.6.   ALLOCATION OF EXPENSES. The Company will pay all Registration
     Expenses for all registrations under this Agreement; PROVIDED, HOWEVER,
     that: (a) if a registration under Section 2.1 is withdrawn at the request
     of the Registration Initiating Investors (other than as a result of
     information concerning the business or financial condition of the Company
     that is made known to the Registration Selling Investors after the date on
     which such registration was requested), the Registration Selling Investors
     may pay the Registration Expenses of such registration pro rata in
     accordance with the number of their Series D-1 Registrable Shares included
     in such registration in order that, in accordance with Section 2.1(d), such
     registration shall not be counted as a registration requested under Section
     2.1; and (b) the Company shall not be obligated to pay fees and expenses of
     Registration Selling Investors Counsel to the extent those fees and
     expenses exceed $50,000 with respect to a registration for an underwritten
     offering or $20,000 with respect to a registration for any other offering.

            2.7.   INDEMNIFICATION AND CONTRIBUTION

                   (a)    In the event of any registration of any of the
            Registrable Shares under the Securities Act pursuant to this
            Agreement, the Company shall indemnify and hold harmless each

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<Page>

            Registration Selling Investor and each underwriter of such
            Registrable Shares, their respective partners, members, agents,
            directors, officers, fiduciaries, investment advisors, brokers
            (including brokers who offer and sell Registrable Securities as
            principal as a result of a pledge or any failure to perform under a
            margin call of Common Stock) and employees of each of them, and each
            other Person, if any, who controls such Registration Selling
            Investor or underwriter within the meaning of the Securities Act or
            the Exchange Act and the officers, directors, partners, members,
            agents and employees of each such controlling Person (each such
            Person an "Investor Indemnified Person"), to the fullest extent
            permitted by applicable law, from and against any and all losses,
            claims, damages, liabilities, settlement costs and expenses, as
            incurred, joint or several, that arise out of, relate to or are
            based upon (i) any untrue statement or alleged untrue statement of
            any material fact contained in any Registration Statement under
            which such Registrable Shares were registered under the Securities
            Act, any preliminary prospectus or final prospectus contained in the
            Registration Statement or any amendment or supplement to such
            Registration Statement or Prospectus, (ii) the omission or alleged
            omission to state a material fact required to be stated therein or
            necessary to make the statements therein not misleading, or (iii)
            any violation or alleged violation by the Company of the Securities
            Act, the Exchange Act, any state securities law or any rule or
            regulation promulgated under the Securities Act, the Exchange Act or
            any state securities law in connection with the Registration
            Statement or the offering contemplated thereby; and the Company will
            reimburse such Investor Indemnified Person for any legal or any
            other expenses reasonably incurred by such Investor Indemnified
            Person in connection with investigating or defending any such loss,
            claim, damage, liability or action; PROVIDED, HOWEVER, that the
            Company will not be liable to any Investor Indemnified Person, in
            any such case to the extent that any such loss, claim, damage or
            liability arises out of or is based upon any untrue statement or
            omission made in such Registration Statement, preliminary prospectus
            or prospectus, or any such amendment or supplement, in reliance upon
            and in conformity with information furnished to the Company, in
            writing, by such Person specifically for use in the preparation
            thereof.

                   (b)    In the event of any registration of any of the
            Registrable Shares under the Securities Act pursuant to this
            Agreement, each Registration Selling Investor, severally and not
            jointly, will indemnify and hold harmless the Company, each of its
            directors and officers and each underwriter (if any) and each
            Person, if any, who controls the Company or any such underwriter
            within the meaning of the Securities Act or the Exchange Act,
            against any and all losses, claims, damages, liabilities, settlement
            costs and expenses arising solely out of (i) any untrue statement or
            alleged untrue statement of a material fact contained in any
            Registration Statement under which such Registrable Shares were
            registered under the Securities Act, any preliminary prospectus or
            final prospectus contained in the Registration Statement, or any
            amendment or supplement to the Registration Statement or Prospectus,
            or (ii) any omission or alleged omission to state a material fact
            required to be stated therein or necessary to make the statements
            therein not misleading, if and to the extent (and only to the
            extent) that the statement or omission was made in reliance upon and
            in conformity with information relating to such Registration Selling
            Investor furnished in writing to the Company by such Registration
            Selling Investor specifically for use in connection with the
            preparation of such Registration Statement, prospectus, amendment or
            supplement; PROVIDED, HOWEVER, that the obligations of a
            Registration Selling Investor hereunder shall be limited to an
            amount equal to the net proceeds to such Registration Selling
            Investor of Registrable Shares sold in connection with such
            registration.

                   (c)    Each Indemnified Person shall give notice to the
            Indemnifying Person promptly after such Indemnified Person has
            actual knowledge of any claim as to which indemnity may

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<Page>

            be sought, and shall permit the Indemnifying Person to assume the
            defense of any such claim or any litigation resulting therefrom;
            PROVIDED, that counsel for the Indemnifying Person, who shall
            conduct the defense of such claim or litigation, shall be approved
            by the Indemnified Person (whose approval shall not be unreasonably
            withheld, conditioned or delayed); and, PROVIDED, FURTHER, that the
            failure of any Indemnified Person to give notice as provided herein
            shall not relieve the Indemnifying Person of its obligations under
            this Section 2.7 except to the extent that the Indemnifying Person
            is actually prejudiced by such failure. The Indemnified Person may
            participate in such defense at such party's expense; PROVIDED,
            HOWEVER, that the Indemnifying Person shall pay such expense if the
            Indemnified Person reasonably concludes that representation of such
            Indemnified Person by the counsel retained by the Indemnifying
            Person would be inappropriate due to actual or potential differing
            interests between the Indemnified Person and any other party
            represented by such counsel in such proceeding; PROVIDED further
            that in no event shall the Indemnifying Person be required to pay
            the expenses of more than one law firm per jurisdiction as counsel
            for the Indemnified Person. The Indemnifying Person also shall be
            responsible for the expenses of such defense if the Indemnifying
            Person does not elect to assume such defense. No Indemnifying
            Person, in the defense of any such claim or litigation shall, except
            with the consent of each Indemnified Person, consent to entry of any
            judgment or enter into any settlement that does not include as an
            unconditional term thereof the giving by the claimant or plaintiff
            to such Indemnified Person of a release from all liability in
            respect of such claim or litigation, and no Indemnified Person shall
            consent to entry of any judgment or settle such claim or litigation
            without the prior written consent of the Indemnifying Person, which
            consent shall not be unreasonably withheld, conditioned or delayed.

                   (d)    In order to provide for just and equitable
            contribution in circumstances in which the indemnification provided
            for in this Section 2.7 is due in accordance with its terms but for
            any reason is held to be unavailable to an Indemnified Person in
            respect to any losses, claims, damages and liabilities referred to
            herein, then the Indemnifying Person shall, in lieu of indemnifying
            such Indemnified Person, contribute to the amount paid or payable by
            such Indemnified Person as a result of such losses, claims, damages
            or liabilities to which such party may be subject in such proportion
            as is appropriate to reflect the relative fault of the Company on
            the one hand and the Registration Selling Investors on the other in
            connection with the statements or omissions that resulted in such
            losses, claims, damages or liabilities. The relative fault of the
            Company and the Registration Selling Investors shall be determined
            by reference to, among other things, whether the untrue or alleged
            untrue statement of material fact related to information supplied by
            the Company or the Registration Selling Investors and the parties'
            relative intent, knowledge, access to information and opportunity to
            correct or prevent such statement or omission. The Company and the
            Registration Selling Investors agree that it would not be just and
            equitable if contribution pursuant to this Section 2.7(d) were
            determined by pro rata allocation or by any other method of
            allocation that does not take account of the equitable
            considerations referred to above. Notwithstanding the provisions of
            this Section 2.7(d), in no case shall any one Registration Selling
            Investor be liable or responsible for any amount in excess of the
            net proceeds received by such Registration Selling Investor from the
            offering of Registrable Shares; PROVIDED, HOWEVER, that no Person
            guilty of fraudulent misrepresentation (within the meaning of
            Section 11(f) of the Securities Act) shall be entitled to
            contribution from any Person who was not guilty of such fraudulent
            misrepresentation. Any party entitled to contribution will, promptly
            after receipt of notice of commencement of any action, suit or
            proceeding against such party in respect of which a claim for
            contribution may be made against another party or parties under this
            Section 2.7(d), notify such party or parties from whom contribution
            may be sought, but the omission so to notify such party or parties
            from whom contribution may be sought shall not relieve such party
            from

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<Page>

            any other obligation it or they may have thereunder or otherwise
            under this Section 2.7(d). No party shall be liable for contribution
            with respect to any action, suit, proceeding or claim settled
            without its prior written consent, which consent shall not be
            unreasonably withheld, conditioned or delayed.

                   (e)    The indemnity and contribution agreements contained in
            this Section are in addition to any other liability that any
            Indemnifying Person may have to any Indemnified Person.

            2.8.   OTHER MATTERS WITH RESPECT TO UNDERWRITTEN OFFERINGS. In the
     event that Series D-1 Registrable Shares are sold pursuant to a
     Registration Statement in an underwritten offering pursuant to Section 2.1,
     the Company agrees to (a) enter into an underwriting agreement containing
     customary representations and warranties with respect to the business and
     operations of the Company and customary covenants and agreements to be
     performed by the Company, including customary provisions with respect to
     indemnification by the Company of the underwriters of such offering; (b)
     use all commercially reasonable efforts to cause its legal counsel to
     render customary opinions to the underwriters with respect to the
     Registration Statement; and (c) use all commercially reasonable efforts to
     cause its independent public accounting firm to issue customary "cold
     comfort letters" to the underwriters with respect to the Registration
     Statement.

            2.9.   INFORMATION BY HOLDER. Each holder of Registrable Shares
     included in any registration shall furnish to the Company such customary
     information regarding such holder and the distribution proposed by such
     holder as the Company may reasonably request in writing and that is
     required under applicable laws, rules and regulations.

            2.10.  "LOCK-UP" AGREEMENT; CONFIDENTIALITY OF NOTICES

                   (a)    Each Series D-2 Investor that Beneficially Owns 5.0%
            or more of the outstanding Common Stock on the date of the filing of
            an initial registration statement for an underwritten offering (a
            "5% Series D-2 Investor") and each Series D-1 Investor, in each case
            if requested by the Company and the managing underwriter of such
            underwritten offering, shall not Transfer any Registrable Shares or
            other securities of the Company held by such Series D-1 Investor or
            5% Series D-2 Investor for a period of 90 days following the
            effective date of the Registration Statement for such underwritten
            offering and shall enter into customary separate agreements to such
            effect as reasonably requested by the Company and such managing
            underwriter; PROVIDED that substantially all executive officers and
            directors (other than Series D-1 Directors) of the Company enter
            into similar agreements as required by the underwriter. The Company
            may impose stop-transfer instructions with respect to the
            Registrable Shares or other securities owned by any such Series D-1
            Investor or 5% Series D-2 Investor subject to the foregoing
            restriction until the end of such 90-day period.

                   (b)    Any Investor receiving any written notice from the
            Company regarding the Company's plans to file a Registration
            Statement shall treat such notice confidentially and shall not
            disclose such information to any Person other than as necessary to
            exercise its rights under this Agreement.

            2.11.  TERMINATION. The rights and obligations of an Investor under
     this Section 2 shall terminate on the first date on which such Investor no
     longer holds any Registrable Shares, except that the rights and obligations
     of the Company and the Registration Selling Investors under Section 2.7
     shall survive the termination of any and all other provisions of this
     Agreement.

     3.     PREEMPTIVE RIGHTS

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            3.1.   RIGHTS OF INVESTORS

                   (a)    The Company shall not issue, sell or exchange, agree
            to issue, sell or exchange, or reserve or set aside for issuance,
            sale or exchange, any Company-Offered Securities, unless in each
            such case the Company shall have first complied with this Section
            3.1. The Company shall deliver to each Investor a Company Offer,
            which shall (i) identify and describe the Company-Offered
            Securities, (ii) describe the price (expressed in either a fixed
            dollar amount or a definitive formula pursuant to which the only
            variable is the market price of the Common Stock at or near the time
            of the proposed issuance, sale or exchange) and other terms upon
            which they are to be issued, sold or exchanged, and the number or
            amount of the Company-Offered Securities to be issued, sold or
            exchanged, (iii) identify the Persons (if known) to which or with
            which the Company-Offered Securities are to be offered, issued, sold
            or exchanged, and (iv) offer to issue and sell to or exchange with
            such Investor that is an Accredited Investor (a) such Accredited
            Investor's Company-Offer Basic Amount and (b) such Accredited
            Investor's Company-Offer Unsubscribed Amount. Notwithstanding the
            other provisions of this Section 3.1, after delivery of the Company
            Offer, the Company may issue, sell or exchange, agree to issue, sell
            or exchange, or reserve or set aside for issuance, sale or exchange,
            Company-Offered Securities to the offerees or purchasers described
            in the Company Offer and upon the terms and conditions (including
            unit prices and interest rates) that are not more favorable, in the
            aggregate, to the acquiring Person or Persons than those set forth
            in the Company Offer without complying with the terms of this
            Section 3.1, PROVIDED that the Company permits each Accredited
            Investor to purchase the number of Company-Offered Securities that
            such Accredited Investor is entitled to purchase pursuant to this
            Section 3.1 on substantially the same terms as the Company sold the
            Company-Offered Securities in the initial transaction, within 20
            days after the Company receives a Company-Offer Acceptance from such
            Accredited Investor.

                   (b)    To accept a Company Offer, in whole or in part, an
            Accredited Investor must deliver to the Company, on or prior to the
            date 15 days after the date of delivery of the Company Offer, a
            Company-Offer Acceptance providing a representation letter
            certifying that such Accredited Investor is an accredited investor
            within the meaning of Rule 501 under the Act and indicating the
            portion of the Accredited Investor's Company-Offer Basic Amount that
            such Accredited Investor elects to purchase and, if such Accredited
            Investor shall elect to purchase all of its Company-Offer Basic
            Amount, the Company-Offer Unsubscribed Amount (if any) that such
            Accredited Investor elects to purchase. If the Company-Offer Basic
            Amounts subscribed for by all Accredited Investors are less than the
            total of all of the Company-Offer Basic Amounts available for
            purchase, then each Accredited Investor who has set forth a
            Company-Offer Unsubscribed Amount in its Company-Offer Acceptance
            shall be entitled to purchase, in addition to the Company-Offer
            Basic Amounts subscribed for, the Company-Offer Unsubscribed Amount
            it has subscribed for; PROVIDED, HOWEVER, that if the Company-Offer
            Unsubscribed Amounts subscribed for exceed the Company-Offer
            Available Unsubscribed Amount, each Accredited Investor who has
            subscribed for any Company-Offer Unsubscribed Amount shall be
            entitled to purchase only that portion of the Company-Offer
            Available Unsubscribed Amount as the Company-Offer Unsubscribed
            Amount subscribed for by such Accredited Investor bears to the total
            Company-Offer Unsubscribed Amounts subscribed for by all Investors,
            subject to rounding by the Board of Directors to the extent it deems
            reasonably necessary.

                   (c)    The Company shall have 90 days from the expiration of
            the period set forth in Section 3.1(b) to issue, sell or exchange
            all or any part of the Company-Offer Refused Securities, but only to
            the offerees or purchasers described in the Company Offer (if so

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            described therein) and only upon terms and conditions (including
            unit prices and interest rates) that are not more favorable, in the
            aggregate, to the acquiring Person or Persons than those set forth
            in the Company Offer.

                   (d)    In the event the Company shall propose to sell less
            than all the Company-Offer Refused Securities, then each Accredited
            Investor may, at its sole option and in its sole discretion, reduce
            the number or amount of the Company-Offered Securities specified in
            its Company-Offer Acceptance to an amount that shall be not less
            than the number or amount of the Company-Offered Securities that the
            Accredited Investor elected to purchase pursuant to Section 3.1(b)
            multiplied by a fraction, (i) the numerator of which shall be the
            number or amount of Company-Offered Securities the Company actually
            proposes to issue, sell or exchange (including Company-Offered
            Securities to be issued or sold to Accredited Investors pursuant to
            Section 3.1(b) prior to such reduction) and (ii) the denominator of
            which shall be the original amount of the Company-Offered
            Securities. In the event that any Accredited Investor so elects to
            reduce the number or amount of Company-Offered Securities specified
            in its Company-Offer Acceptance, the Company may not issue, sell or
            exchange more than the reduced number or amount of the
            Company-Offered Securities unless and until such securities have
            again been offered to the Accredited Investors in accordance with
            Section 3.1(a).

                   (e)    Upon (i) the closing of the issuance, sale or exchange
            of all or less than all of the Company-Offer Refused Securities or
            (ii) such other date agreed to by the Company and Accredited
            Investors who have subscribed for a majority of the Company-Offered
            Securities subscribed for by the Accredited Investors, such
            Accredited Investor or Investors shall acquire from the Company and
            the Company shall issue to such Accredited Investor or Investors,
            the number or amount of Company-Offered Securities specified in the
            Investor Offers of Acceptance, as reduced pursuant to Section 3.1(d)
            if any of the Accredited Investors has so elected, upon the terms
            and conditions specified in the Company Offer.

                   (f)    The purchase by the Accredited Investors of any
            Company-Offered Securities is subject in all cases to the
            preparation, execution and delivery by the Company and the
            Accredited Investors of a purchase agreement relating to such
            Company-Offered Securities reasonably satisfactory in form and
            substance to the Accredited Investors and their respective counsel.

                   (g)    Company-Offered Securities not acquired by the
            Accredited Investors or other Persons in accordance with Section
            3.1(c) may not be issued, sold or exchanged until they are again
            offered to the Accredited Investors under the procedures specified
            in this Agreement.

            3.2.   EXCLUDED TRANSACTIONS. The rights of the Accredited Investors
     under Section 3.1 shall not apply to:

                   (a)    the issuance of securities of the Company for
                          consideration other than cash, including the issuance
                          of shares (i) as a stock dividend to holders of Common
                          Stock, Shares or any other Company securities, or upon
                          any subdivision or combination of shares of Common
                          Stock, Shares or any other Company securities, and
                          (ii) upon exercise or conversion of preferred stock,
                          options, warrants or debt securities exercisable or
                          convertible for Common Stock pursuant to their terms;

                   (b)    the issuance of Common Stock or options to purchase
                          Common Stock to employees, directors or consultants of
                          the Company or any Subsidiary pursuant to a stock
                          option plan, employee stock purchase plan or other
                          equity incentive plan or arrangement approved by the
                          Board of Directors of the Company and by a majority

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                          of the Independent Directors;

                   (c)    the issuance of securities solely in consideration for
                          the acquisition (whether by merger or otherwise) by
                          the Company or any of its subsidiaries of all or
                          substantially all of the stock or assets of such
                          entity;

                   (d)    the issuance of securities of the Company in a
                          firm-commitment underwritten public offering pursuant
                          to an effective Registration Statement;

                   (e)    the issuance of securities of the Company, or the
                          grant of options or warrants therefor, in connection
                          with any present or future borrowing, line of credit,
                          leasing or similar financing arrangement approved by
                          the Board of Directors of the Company and by a
                          majority of the Independent Directors; or

                   (f)    the issuance of securities in connection with any
                          transaction with a strategic investor, vendor, lessor,
                          customer, supplier, marketing partner, developer or
                          integrator or any similar arrangement, in each case
                          the primary purpose of which is not to raise equity
                          capital, approved by the Board of Directors of the
                          Company and by a majority of the Independent
                          Directors.

     In addition, the rights under Section 3.1 of Accredited Investors that are
     (i) Series D-1 Investors shall not apply to an issuance of securities as to
     which Series D-1 Investors holding not less than a majority of the Series
     D-1 Stock have delivered to the Company a written notice to the effect that
     Series D-1 Investors have waived their right to participate in the
     contemplated offering under Section 3.1, or (ii) Series D-2 Investors shall
     not apply to an issuance of securities as to which Series D-2 Investors
     holding not less than a majority of the Series D-2 Stock have delivered to
     the Company a written notice to the effect that Series D-2 Investors have
     waived their right to participate in the contemplated offering under
     Section 3.1.

            3.3.   TERMINATION. The rights of an Investor under this Section 3
     shall terminate upon the earlier of (a) the first date on which the
     Investors, in the aggregate, hold less than 10% of the Shares originally
     issued on the date hereof and (b) the closing of a Company Sale.

     4.     COVENANTS OF THE COMPANY

            4.1.   INFORMATION REQUIREMENTS. The Company shall furnish to each
     Investor:

                   (a)    promptly after filing, a copy of each report or other
                          document (including any schedules or exhibits thereto)
                          that is filed by the Company with the Commission under
                          the Securities Act or the Exchange Act and that is
                          available to the general public; PROVIDED that no such
                          copy shall be required if such report was filed using
                          the Electronic Data Gathering, Analysis, and Retrieval
                          system of the Commission; and

                   (b)    contemporaneously with delivery to holders of Common
                          Stock, a copy of each report or other document (other
                          than any document filed with the Commission under the
                          Securities Act or the Exchange Act) delivered to
                          holders of Common Stock.

            4.2.   BOARD OF DIRECTORS. For so long as any director is serving at
     the election of the holders of Series D-1 Stock pursuant to the Series D
     Certificate:

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                   (a)    The Company shall reimburse the Series D-1 Directors
            for their reasonable out-of-pocket expenses incurred in attending
            meetings of the Board of Directors of the Company or any committee
            thereof, to the extent provided in, and in accordance with, the
            Company's reimbursement policy in effect from time to time with
            respect to other directors who are not employees of the Company or a
            Subsidiary. The Series D-1 Directors shall be entitled to receive
            such fees or other compensation as may be paid by the Company from
            time to time to directors who are not employees of the Company or a
            Subsidiary.

                   (b)    The Company's Certificate of Incorporation shall at
            all times provide for the indemnification of the members of the
            Board of Directors to the fullest extent provided by the Delaware
            General Corporation Law. In the event that the Company or any of its
            successors or assigns (i) consolidates with or mergers into any
            other entity and shall not be the continuing or surviving
            corporation in such consolidation or merger or (ii) Transfers all or
            substantially all of its properties and assets to any entity, then,
            and in each such case, to the extent necessary, proper provision
            shall be made so that the successors and assigns of the Company
            assume the obligations of the Company with respect to
            indemnification of members of the Board of Directors as contained in
            the Company's Certificate of Incorporation.

                   (c)    The Company shall use all commercially reasonable
            efforts to carry and maintain any insurance against directors' and
            officers' liability to cover such directors to the same extent as
            directors elected by the holders of Common Stock; PROVIDED, HOWEVER,
            that if the aggregate annual premiums for such insurance exceed 200%
            of the per annum rate of premium currently paid by the Company on
            the date of this Agreement for such insurance, then the Company
            shall provide, at a minimum, the maximum coverage that shall then be
            available at an annual premium equal to 200% of such rate; PROVIDED,
            HOWEVER, that in no event should the coverage afforded the Series
            D-1 Directors be less favorable in any respect than the coverage
            afforded directors elected by the holders of Common Stock.

            4.3.   REPORTS UNDER SECURITIES EXCHANGE ACT OF 1934. With a view to
     making available to the Investors the benefits of Rule 144 and any other
     rule or regulation of the Commission that may at any time permit a Holder
     to sell securities of the Company to the public without registration, and
     with a view to making it possible for Investors to have the Registrable
     Shares registered for resale pursuant to a registration on Form S-3 (or any
     successor form), the Company shall:

                   (a)    use all commercially reasonable efforts to make and
                          keep current public information about the Company
                          available, as those terms are understood and defined
                          in Rule 144, at all times;

                   (b)    use its best efforts to file with the Commission in a
                          timely manner all reports and other documents required
                          of the Company under the Securities Act and the
                          Exchange Act; and

                   (c)    furnish to any Investor upon request (i) a written
                          statement by the Company as to its compliance with the
                          reporting requirements of Rule 144 and (ii) such other
                          reports and documents of the Company as such Investor
                          may reasonably request to avail itself of any similar
                          rule or regulation of the Commission allowing it to
                          sell any Registrable Shares without registration.

            4.4.   REGISTRATION RIGHTS. The Company shall not enter into any
     Other Registration Rights with any Other Registration Rights Holder unless
     such Other Registration Rights do not conflict with the provisions of this
     Agreement. Such Other Registration Rights shall not be deemed to conflict
     with this Agreement solely as a result of a grant of incidental
     registration rights to the Other

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     Registration Rights Holders with respect to a Registration Statement filed
     pursuant to Section 2.1, PROVIDED that:

                   (a)    Investors are granted the right to exercise incidental
                          registration rights with respect to any registration
                          required by such Other Registration Rights Holders to
                          be made by the Company;

                   (b)    if a managing underwriter advises the Company that
                          marketing factors require a limitation on the number
                          of shares to be underwritten in an offering made at
                          the request of the Other Registration Rights Holders,
                          the shares held by the Investors shall be excluded
                          first, before any shares of such Other Registration
                          Rights Holders are excluded; and

                   (c)    if a managing underwriter advises the Company that
                          marketing factors require a limitation on the number
                          of shares to be underwritten in an offering requested
                          under Section 2.1, the shares held by such Other
                          Registration Rights Holders shall be excluded first,
                          before any shares of the Investors are excluded.

            4.5.   AVAILABLE COPY. The Secretary of the Company shall maintain
     an original copy of this Agreement, duly executed by each of the parties
     hereto, at the principal executive office of the Company and shall make
     such copy available for inspection by any Person requesting it.

            4.6.   TERMINATION. The rights of an Investor under this Section 4
     shall terminate upon the first date on which such Investor no longer holds
     any Shares, PROVIDED that Section 4.4 shall terminate upon the earlier of
     (A) the first date on which such Investor no longer holds any Shares, and
     (B) the closing of a Company Sale.

     5.     TRANSFER RESTRICTIONS

            5.1.   PROHIBITION. Any Transfer, whether direct or indirect, of any
     of the Shares or Registrable Shares by an Investor, other than according to
     the terms of this Agreement, shall be void and convey no right, title, or
     interest in or to any of such Shares or Registrable Shares to the purported
     transferee.

            5.2.   RESTRICTIONS. No Investor shall Transfer any Shares or
     Registrable Shares or any legal or beneficial interest therein except for:

                   (a)    Transfers of Registrable Shares pursuant to a bona
                          fide public offering under a Registration Statement
                          filed with the Commission under the Securities Act,
                          including pursuant to the exercise of rights granted
                          in Section 2;

                   (b)    Transfers of Registrable Shares pursuant to Rule 144;

                   (c)    Transfers of Shares to any non-Affiliate (other than a
                          Competitor), PROVIDED that (i) immediately after
                          giving effect to such Transfer, the Investor
                          reasonably believes the transferee Beneficially Owns
                          less than 10% of the outstanding Common Stock, and
                          (ii) such transferee delivers to the Company and the
                          Investors a written instrument, in form and substance
                          reasonably acceptable to the Company, agreeing to be
                          bound by the terms of this Agreement as if such
                          transferee were an Investor;

                   (d)    Transfers of Shares or Registrable Shares to an
                          Affiliate of such Investor (or to any investor in such
                          Affiliate of such Investor pursuant to a pro rata
                          liquidation or

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                          distribution), PROVIDED that such transferee delivers
                          to the Company and the Investors a written instrument,
                          in form and substance reasonably acceptable to the
                          Company, agreeing to be bound by the terms of this
                          Agreement as if such transferee were an Investor;

                   (e)    Transfers of Shares or Registrable Shares pursuant to
                          a bona fide public offer that is subject to the
                          provisions of Regulation 14D or Rule 13e-3 under the
                          Exchange Act (or any successor regulation, rule or
                          statute) by a Person to purchase or exchange for cash
                          or other consideration any shares of Common Stock and
                          that consists of an offer to acquire more than 25% of
                          the then-outstanding Common Stock, PROVIDED that such
                          offer is not made by and does not include (i) the
                          Company, an Investor, or an Affiliate of the Company
                          or any Investor or (ii) any group (within the meaning
                          of Section 13(d) of the Exchange Act) formed for the
                          purpose of acquiring, holding, voting or disposing of
                          Common Stock that includes the Company, an Investor,
                          or an Affiliate of the Company or any Investor; or

                   (f)    Transfers of Shares or Registrable Shares pursuant to
                          a merger, consolidation or reorganization to which the
                          Company is a party.

            5.3.   LEGENDS.

                   (a)    Each Series D-1 Investor agrees to the imprinting on
            certificates representing such Investor's Shares or Registrable
            Shares of a legend substantially to the following effect:

            "THE SHARES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN
            REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, AND
            MAY NOT BE SOLD, TRANSFERRED, DISTRIBUTED OR OTHERWISE DISPOSED
            OF IN THE ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT UNDER
            SUCH ACT OR AN OPINION OF COUNSEL SATISFACTORY TO THE
            CORPORATION TO THE EFFECT THAT SUCH REGISTRATION IS NOT
            REQUIRED. THE SALE OR OTHER DISPOSITION OF ANY OF THE SHARES
            REPRESENTED BY THIS CERTIFICATE IS RESTRICTED BY AN INVESTOR
            RIGHTS AGREEMENT DATED AS OF __________, 2003 BY AND AMONG THIS
            CORPORATION AND CERTAIN OF THE STOCKHOLDERS OF THIS
            CORPORATION. A COPY OF SUCH AGREEMENT IS AVAILABLE FOR
            INSPECTION DURING NORMAL BUSINESS HOURS AT THE PRINCIPAL
            EXECUTIVE OFFICE OF THIS CORPORATION."

            The legend set forth above shall be removed if and when (a) the
            securities represented by such certificate are disposed of pursuant
            to an effective Registration Statement or (b) the Series D-1
            Investor delivers to the Company an opinion of counsel reasonably
            acceptable to the Company to the effect that such legend may be
            removed.

                   (b)    Each Series D-2 Investor agrees to the imprinting, so
            long as is required by this Section 5.3(b), of the following legend
            on any certificate evidencing Series D-2 Securities:

            "THESE SECURITIES HAVE NOT BEEN REGISTERED WITH THE SECURITIES
            AND EXCHANGE COMMISSION OR THE SECURITIES COMMISSION OF ANY
            STATE IN RELIANCE UPON AN EXEMPTION FROM REGISTRATION UNDER THE
            SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), AND,
            ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT TO AN
            EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT OR
            PURSUANT TO AN AVAILABLE EXEMPTION FROM THE REGISTRATION
            REQUIREMENTS OF THE SECURITIES ACT AND IN COMPLIANCE WITH
            APPLICABLE STATE SECURITIES OR BLUE SKY LAWS. THESE SECURITIES
            AND THE SECURITIES ISSUABLE UPON EXERCISE OF THESE SECURITIES
            MAY BE PLEDGED IN CONNECTION WITH A BONA FIDE MARGIN

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            ACCOUNT OR OTHER LOAN SECURED BY SUCH SECURITIES."

            Certificates evidencing Series D-2 Securities shall not be required
            to contain such legend or any other legend (i) pursuant to or
            following any sale of such Series D-2 Securities pursuant to an
            effective Registration Statement covering the resale of such Series
            D-2 Securities under the Securities Act, (ii) following any sale of
            such Series D-2 Securities pursuant to Rule 144, (iii) if such
            Series D-2 Securities are eligible for sale under Rule 144(k), or
            (iv) if such legend is not, in the reasonable opinion of the Company
            counsel, required under the circumstances under applicable
            requirements of the Securities Act (including judicial
            interpretations and pronouncements issued by the Staff of the
            Commission). Following the effectiveness of the Shelf Registration
            Statement or at such earlier time as a legend is no longer required
            for certain Series D-2 Securities, the Company will, no later than
            three Trading Days following the delivery by a Series D-2 Investor
            to the Company or the Company's transfer agent of a legended
            certificate representing such Series D-2 Securities, deliver or
            cause to be delivered to such Series D-2 Investor a certificate
            representing such Series D-2 Securities that is free from all
            restrictive and other legends. The Company may not make any notation
            on its records or give instructions to any transfer agent of the
            Company that enlarge the restrictions on transfer set forth in this
            Section, except as may be required by applicable law.

            5.4.   ACKNOWLEDGEMENT. The Company acknowledges and agrees that a
     Series D-2 Investor may from time to time pledge pursuant to a bona fide
     margin agreement or grant a security interest in some or all of the Series
     D-2 Securities and, if required under the terms of such arrangement, such
     Series D-2 Purchaser may transfer pledged or secured Series D-2 Securities
     to the pledgees or secured parties. Such a pledge or transfer would not be
     subject to approval of the Company and no legal opinion of the pledgee,
     secured party or pledgor shall be required in connection therewith except
     as required by applicable law. Further, no notice shall be required of such
     pledge. At the appropriate Series D-2 Investor's expense, the Company will
     execute and deliver such reasonable documentation as a pledgee or secured
     party of Series D-2 Securities may reasonably request in connection with a
     pledge or transfer of the Series D-2 Securities, including the preparation
     and filing of any required prospectus supplement under Rule 424(b)(3) of
     the Securities Act or other applicable provision of the Securities Act to
     appropriately amend the list of Selling Stockholders thereunder.

     6.     STANDSTILL AGREEMENTS

            6.1.   RESTRICTIONS

                   (a)    No Series D-1 Investor shall, directly or indirectly,
            unless specifically permitted by this Agreement or authorized or
            consented to do so in writing in advance by the Company:

                          (i)    except for shares or securities acquired as a
                                 dividend or distribution on the Shares, acquire
                                 or agree, offer, seek or propose to acquire, or
                                 cause to be acquired, Beneficial Ownership of
                                 any shares of Common Stock, or any options,
                                 warrants or other rights (including any
                                 convertible or exchangeable securities) to
                                 acquire any shares of Common Stock, to the
                                 extent that such acquisition would result in an
                                 increase in such Investor's (or Affiliate's, as
                                 the case may be) percentage Beneficial
                                 Ownership of Common Stock above the percentage
                                 Beneficial Ownership of Common Stock as of the
                                 date of this Agreement;

                          (ii)   make, or in any way participate in, any
                                 "solicitation" of "proxies" (as such terms are
                                 defined in Rule 14a-1 under the Exchange Act)
                                 with respect to the

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                                 voting of any securities of the Company;

                          (iii)  deposit any securities of the Company in a
                                 voting trust or subject any such securities to
                                 any arrangement or agreement with any Person
                                 (other than one or more Investors or
                                 Affiliates);

                          (iv)   form, join, or in any way become a member of
                                 any group within the meaning of Section 13(d)
                                 of the Exchange Act (other than a "group"
                                 consisting solely of Investors and Affiliates
                                 that together Beneficially Own less than a
                                 majority of the Company's outstanding voting
                                 securities);

                          (v)    arrange any financing for, or provide any
                                 financing commitment specifically for, the
                                 purchase by such Investor of any voting
                                 securities or securities convertible or
                                 exchangeable into or exercisable for any voting
                                 securities or assets of the Company, except for
                                 such assets as are then being offered for sale
                                 by the Company; PROVIDED, HOWEVER, that this
                                 clause (v) shall not apply to any such
                                 financing arrangements or commitments to the
                                 extent involving a Transfer of Common Stock
                                 Beneficially Owned by an Investor to any Person
                                 that is not an Investor;

                          (vi)   seek to propose or propose, whether alone or in
                                 concert with other Investors, any tender offer,
                                 exchange offer, merger, business combination,
                                 restructuring, liquidation, recapitalization or
                                 similar transaction involving the Company or
                                 any of the Subsidiaries;

                          (vii)  for so long as holders of Series D-1 Stock are
                                 entitled to elect Series D-1 Directors pursuant
                                 to the Series D Certificate, nominate any
                                 Person for election by the holders of Common
                                 Stock as a director of the Company who is not
                                 nominated by the then-incumbent directors, or
                                 propose any matter to be voted upon by the
                                 stockholders of the Company (other than for an
                                 Affiliate of such Investor acting in his or her
                                 capacity as a director of the Company);

                          (viii) authorize or direct any of its directors,
                                 officers, employees, agents or other
                                 representatives acting in any such capacities
                                 to take any action described in clauses (i)
                                 through (vii) above;

                          (ix)   solicit, initiate, or knowingly or
                                 intentionally facilitate the taking of any
                                 action by an Affiliate of such Series D-1
                                 Investor (that is not itself an Investor) that
                                 would be prohibited by this Section 6.1 if such
                                 Affiliate were an Investor; or

                          (x)    publicly announce or disclose any intention,
                                 plan or arrangement inconsistent with the
                                 foregoing.

            Notwithstanding the foregoing, a Series D-1 Investor shall not be
            prohibited from taking any action described in clauses (i) through
            (x) to the extent such action is taken in response to, and in
            competition with, a similar action that has been undertaken by a
            Person who is not an Investor.

                   (b)    No Series D-1 Investor will, nor will it authorize or
            permit any of its directors, officers, employees, agents or other
            representatives acting in any such capacities to, take any action
            that would require the Company to make a public announcement
            regarding any of the matters set forth in Section 6.1(a).

24
<Page>

                   (c)    Anything in this Section 6.1 to the contrary
            notwithstanding, this Section 6.1 shall not prohibit or restrict (i)
            the voting of securities of the Company held by the Series D-1
            Investors or (ii) any disclosure pursuant to Section 13(d) of the
            Exchange Act that a Series D-1 Investor reasonably believes, after
            consulting with outside counsel, is required in connection with any
            action taken by a Series D-1 Investor pursuant to Section 6.1(b).

            6.2.   CERTAIN PERMITTED TRANSACTIONS AND COMMUNICATIONS. Anything
     in Section 6.1 to the contrary notwithstanding, Section 6.1 shall not
     prohibit (a) the conversion of Series D-1 Stock, the exercise of the Series
     D-1 Warrants, or the consummation by a Series D-1 Investor of any
     transaction expressly provided for in this Agreement, PROVIDED that if such
     transaction is to be consummated on or before the earliest of (i) June 15,
     2005, (ii) the first date on which none of the Convertible Debentures
     remains outstanding, and (iii) the first date on which the provision in the
     Convertible Debentures requiring redemption upon a Change of Control (as
     defined in the indenture governing the Convertible Debentures) is not in
     effect, then such Series D-1 Investor (which for this purpose shall include
     any syndicate or group that includes such Series D-1 Investor and that
     would be deemed to be a person under Section 13(d)(3) of the Exchange Act)
     shall not, without the prior written consent of the Company, be entitled to
     consummate such transaction to the extent such Series D-1 Investor
     (including any such syndicate or group) would thereafter Beneficially Own
     more than 49.9% of the then-outstanding voting securities of the Company
     (any voting securities of which such Series D-1 Investor is the Beneficial
     Owner that are not then outstanding being deemed outstanding for purposes
     of calculating such percentage), Common Stock, (b) any action taken by
     Series D-1 Investors in connection with the nomination and election of the
     Series D-1 Directors or any action taken by the Series D-1 Directors in
     such capacities, (c) officers and employees of the Series D-1 Investors
     from communicating with officers of the Company or its Affiliates on
     matters related to or governed by this Agreement, matters relating to the
     Series D-1 Investors investment in the Company, or operational matters, or
     (d) the Series D-1 Investors from communicating with the Board of
     Directors, the Chairman of the Board of Directors, the Chief Executive
     Officer or the Chief Financial Officer of the Company, so long as any such
     communication is conveyed in confidence, would not require public
     disclosure by the Series D-1 Investors or by the Company, and is not
     intended to elicit, and, in the reasonable belief (after consulting with
     outside counsel) of the Series D-1 Investor making such communication, does
     not require the issuance of, a public response by the Company.

            6.3.   TERMINATION. The obligations of a Series D-1 Investor under
     this Section 6 shall terminate upon the earlier of (a) the first date on
     which such Series D-1 Investor and its Affiliates Beneficially Own less
     than 5% of the outstanding shares of Common Stock, collectively (on an
     as-converted basis), and (b) the closing of a Company Sale.

     7.     TRADING LIMITATIONS

            7.1.   RESTRICTIONS. For so long as an Investor or its Affiliates
     hold Shares, such Investor shall not sell, contract to sell, grant any
     option to purchase, or make any short sale of Common Stock, establish a
     "put equivalent position" (as such term is defined in Rule 16a-1(h) under
     the Exchange Act) or engage in any transaction the result of which would
     involve any of the foregoing, at a time when such Investor has no
     equivalent offsetting long position in Common Stock. For purposes of
     determining whether an Investor has an equivalent offsetting long position
     in the Common Stock, all Common Stock held by such Investor, all shares of
     Common Stock issuable upon conversion of all Shares or upon exercise in
     full of any warrant for Common Stock then held by such Investor (assuming
     that such securities were then fully convertible or exercisable,
     notwithstanding any provisions to the contrary, and giving effect to any
     conversion or exercise price adjustments scheduled to take effect in the
     future), and all shares of Common Stock issuable upon exercise of

25
<Page>

     any call option or "call equivalent position" (as defined in Rule 16a-1(b)
     under the Exchange Act) held by such Investor (assuming that such call
     position was then fully convertible or exercisable, notwithstanding any
     provisions to the contrary, and giving effect to any conversion or exercise
     price adjustments scheduled to take effect in the future) shall be deemed
     to be held long by such Investor.

            7.2.   TERMINATION. The obligations of an Investor under this
     Section 7 shall terminate upon the earlier of (a) the first date on which
     such Investor no longer Beneficially Owns any Shares or Registrable Shares
     and (b) the closing of a Company Sale.

     8.     CONFIDENTIALITY.

            8.1.   RESTRICTIONS. Each Series D-1 Investor agrees that it will
     keep confidential and will not disclose, divulge or use for any purpose,
     other than to monitor its investment in the Company, any Confidential
     Information, unless such Confidential Information (a) is known or becomes
     known to the public in general (other than as a result of a breach of this
     Section 8 by such Series D-1 Investor), (b) is or has been independently
     developed or conceived by the Series D-1 Investor without use of the
     Company's Confidential Information or (c) is or has been made known or
     disclosed to the Series D-1 Investor by a third party unless at the time of
     the proposed disclosure by the Series D-1 Investor, the Series D-1 Investor
     has knowledge that the disclosure was made to the Series D-1 Investor in
     breach of an obligation of confidentiality such third party had to the
     Company; PROVIDED, HOWEVER, that a Series D-1 Investor may disclose
     Confidential Information (i) to its attorneys, accountants, consultants,
     and other professionals to the extent necessary to obtain their services in
     connection with monitoring its investment in the Company, (ii) to any
     prospective purchaser of any Shares from such Series D-1 Investor as long
     as such prospective purchaser agrees to be bound by the provisions of this
     Section 8 and names the Company as a third party beneficiary of such
     agreement, (iii) to any Affiliate, PROVIDED that the Confidential
     Information is disclosed on a confidential basis to such party, or (iv) as
     may otherwise be required by law, legal process or regulatory requirements,
     PROVIDED that the Series D-1 Investor takes reasonable steps to minimize
     the extent of any such required disclosure. Notwithstanding the foregoing,
     such information shall not be deemed confidential for the purpose of
     enforcing this Agreement. The Series D-1 Investor shall be liable for the
     disclosure of any Confidential Information by any Person described in the
     preceding clauses (i) and (iii).

            8.2.   TERMINATION. The obligations of a Series D-1 Investor under
     this Section 8 shall terminate on the second anniversary of the earlier of
     (a) the first date on which such Series D-1 Investor no longer Beneficially
     Owns any Shares or Registrable Shares and (b) the closing of a Company
     Sale.

     9.     ELECTION OF SERIES D-1 DIRECTORS

            9.1.   INITIAL SERIES D-1 DIRECTORS. The Company confirms that its
     Board of Directors has elected, effective contemporaneously with the
     execution and delivery of this Agreement, Douglas A. Kingsley and Michael
     Pehl as directors of the Company. The Series D-1 Investors confirm that
     such individuals shall constitute two of the initial Series D-1 Directors.
     The Company and the Series D-1 Investors agree to take any such further
     actions as may be necessary or desirable (i) to effect the appointment of
     such additional initial Series D-1 Directors as the Series D-1 Investors
     are permitted to designate pursuant to the Series D Certificate and (ii) to
     effect the election, from time to time in the future, of individuals as
     Series D-1 Directors pursuant to the Series D Certificate, subject to the
     provisions of Section 9.2. No individual designated to serve on the Board
     of Directors as a Series D-1 Director shall be deemed to be the deputy of
     or otherwise required to discharge his or her duties under the direction
     of, or with special attention to the interests of, the Series D-1
     Investors.

26
<Page>

            9.2.   DESIGNATION OF SERIES D-1 DIRECTORS. The Company shall
     provide the Series D-1 Investors with 30 days' prior written notice of any
     intended mailing of a notice to stockholders for a meeting at which the
     term of one or more Series D-1 Directors shall expire. Such notice shall
     specify (i) the date of such meeting, (ii) the date on which such mailing
     is intended to be made, and (iii) the name or names of the Series D-1
     Directors whose terms are to expire at such meeting. A Series D-1 Investor
     or Investors holding in the aggregate a majority of the shares of Series
     D-1 Stock then outstanding (not including outstanding shares of Common
     Stock) may give written notice to the other Series D-1 Investors and the
     Company, no later than 15 days after receipt of such notice from the
     Company, of the individuals to be designated by the Board as nominees for
     election as Series D-1 Directors at such meeting. Only the individuals
     designated pursuant to the preceding sentence or otherwise in accordance
     with the Series D Certificate shall be nominated and recommended for
     election as Series D-1 Directors. If Series D-1 Investors fail to give
     notice to the Company as provided above, then the individuals then serving
     as Series D-1 Directors shall be deemed to have been designated for
     reelection.

            9.3.   COVENANT REGARDING COMMON DIRECTORS. In the event one or more
     directors elected by the holders of the Common Stock (voting as a single
     class or with one or more other classes or series of capital stock (the
     "Common Directors")) no longer serves as a member of the Board of Directors
     due to his or her resignation, removal, incapacity or death (the resulting
     vacancy in the Board of Directors being referred to herein as a "Common
     Director Vacancy"), for so long as this Section 9 is in effect and the
     Series D-1 Investors have the right to elect one or more members of the
     Board of Directors pursuant to the terms of the Series D Certificate, the
     Series D-1 Investors hereby covenant and agree as follows:

                   (a)    In the event the Board of Directors elects to fill a
            Common Director Vacancy by vote of the members of the Board of
            Directors then in office, the Series D-1 Investors shall use all
            commercially reasonable efforts to cause the Series D-1 Directors to
            vote for the nominee approved by a majority of the remaining Common
            Directors then in office.

                   (b)    In the event a Common Director Vacancy is filled by a
            person who was not approved by a majority of the Common Directors in
            office (regardless of whether the Series D-1 Investors used all
            commercially reasonable efforts as required by subsection (a)
            above), the Series D-1 Investors shall, notwithstanding their rights
            contained in the Series D Certificate, use commercially reasonable
            efforts to cause a Series D-1 Director to resign and be replaced by
            a person approved by a majority of the Common Directors then in
            office.

            9.4.   TERMINATION. The rights of the Series D-1 Investors under
     this Section 9 shall terminate as of the date on which holders of shares of
     Series D-1 Stock are no longer entitled to elect Series D-1 Directors
     pursuant to the Series D Certificate.

     10.    NONPUBLIC INFORMATION. Notwithstanding any other provision of this
Agreement, neither the Company nor any Person acting on its behalf will provide
any Series D-2 Investor with any material, nonpublic information about the
Company unless such Series D-2 Investor consents to receive such information in
writing in advance even if otherwise required pursuant to the terms of any
Transaction Document (as defined in the Purchase Agreement). The Company
understands and confirms that each of the Series D-2 Investors will rely on the
foregoing covenant in effecting transactions in securities of the Company.

     11.    GENERAL

            11.1.  OWNERSHIP CALCULATIONS

27
<Page>

                   (a)    Except as otherwise expressly provided herein, in
            determining the number or percentage of Shares owned by an Investor
            for purposes of exercising rights under this Agreement, (i) Shares
            owned by an Investor shall be deemed to include Shares that have
            been converted into Common Stock so long as such Common Stock is
            owned by such Investor and (ii) all Shares held by Affiliates shall
            be aggregated together, PROVIDED that no Shares shall be attributed
            to more than one Person within any such group of Affiliates.

                   (b)    In determining the number or percentage of Registrable
            Shares owned by an Investor for purposes of exercising rights under
            this Agreement, the determination shall include shares of Common
            Stock issuable upon conversion, exercise or exchange of securities,
            including the Shares, even if such conversion, exercise or exchange
            has not been effected.

            11.2.  NOTICES. All notices, requests and other communications to
     any party hereunder shall be in writing (including facsimile or similar
     writing) and shall be given to such party at its address or facsimile
     number set forth on the signature page hereof, or such other address or
     facsimile number as such party may hereinafter specify for the purpose of
     this Section to the party giving such notice. Each such notice, request or
     other communication shall be effective (a) if given by facsimile
     transmission, when such facsimile is transmitted to the facsimile number
     specified on the signature pages of this agreement and the appropriate
     confirmation is received or, (b) if given by mail, 72 hours after such
     communication is deposited in the mails with first class postage prepaid,
     addressed as aforesaid or, (c) if given by any other means, when delivered
     at the address specified on the signature pages of this Agreement.

            11.3.  AMENDMENTS AND WAIVERS. This Agreement may be amended or
     terminated and the observance of any term of this Agreement may be waived
     with respect to all parties to this Agreement (either generally or in a
     particular instance and either retroactively or prospectively), with the
     written consent of the Company, Investors holding greater than 50% of the
     Series D-1 Stock then held by Investors and Investors holding greater than
     50% of the Series D-2 Stock then held by Investors; PROVIDED that any
     amendment, termination or waiver to:

                   (a)    any provision of this Agreement that affects only the
                          rights of holders of Series D-1 Stock and has no
                          adverse effect on the rights of holders of Series D-2
                          Stock may be amended with the written consent of the
                          Company and Investors holding greater than 50% of the
                          Series D-1 Stock then held by Investors; PROVIDED that
                          after such amendment such provision continues to
                          affect only the holders of the Series D-1 Stock; and

                   (b)    any provision of this Agreement that affects only the
                          rights of holders of Series D-2 Stock and has no
                          adverse effect on the rights of holders of Series D-1
                          Stock may be amended with the written consent of the
                          Company and Investors holding greater than 50% of the
                          Series D-2 Stock then held by Investors; PROVIDED that
                          after such amendment such provision continues to
                          affect only the holders of the Series D-2 Stock.

     Notwithstanding the foregoing, this Agreement may not be amended or
     terminated and the observance of any term hereunder may not be waived with
     respect to any Investor without the written consent of such Investor unless
     such amendment, termination or waiver applies to all Investors of the same
     series of Series D Preferred Stock in the same fashion (it being agreed
     that a waiver of the provisions of Section 3 with respect to a particular
     transaction shall be deemed to apply to all Accredited Investors in the
     same fashion if such waiver does so by its terms, notwithstanding the fact
     that certain Accredited Investors may nonetheless, by agreement with the
     Company, purchase securities in such transaction). The Company shall give
     prompt written notice

28
<Page>

     of any amendment or termination of this Agreement or waiver hereunder to
     any party hereto that did not consent in writing to such amendment,
     termination or waiver. Any amendment, termination or waiver effected in
     accordance with this Section 10.3 shall be binding on all parties hereto,
     even if they do not execute such consent. No waivers of or exceptions to
     any term, condition or provision of this Agreement, in any one or more
     instances, shall be deemed to be, or construed as, a further or continuing
     waiver of any such term, condition or provision.

            11.4.  GOVERNING LAW; VENUE; WAIVER OF JURY TRIAL. All questions
     concerning the construction, validity, enforcement and interpretation of
     this Agreement shall be governed by and construed and enforced in
     accordance with the internal laws of the State of Delaware. Each party
     hereby irrevocably submits to the exclusive jurisdiction of the state and
     federal courts sitting in the State of Delaware, for the adjudication of
     any dispute hereunder or in connection with any transaction contemplated
     hereby or discussed herein, and hereby irrevocably waives, and agrees not
     to assert in any suit, action or proceeding, any claim that it is not
     personally subject to the jurisdiction of any such court, that such suit,
     action or proceeding is improper. Each party hereby irrevocably waives
     personal service of process and consents to process being served in any
     such suit, action or proceeding by mailing a copy thereof via registered or
     certified mail or overnight delivery (with evidence of delivery) to such
     party at the address in effect for notices to it under this Agreement and
     agrees that such service shall constitute good and sufficient service of
     process and notice thereof. Nothing contained herein shall be deemed to
     limit in any way any right to serve process in any manner permitted by law.
     Each of the parties hereby waives all rights to a trial by jury.

            11.5.  COUNTERPARTS; FACSIMILE SIGNATURES. This Agreement may be
     executed in any number of counterparts (including facsimile signature),
     each of which shall be an original with the same effect as if the
     signatures thereto and hereto were upon the same instrument. No provision
     of this Agreement is intended to confer upon any Person other than the
     parties hereto any rights or remedies hereunder, except to the extent
     expressly provided herein.

            11.6.  ENTIRE AGREEMENT. This Agreement constitutes the entire
     agreement and understanding among the parties hereto with respect to the
     subject matter of this Agreement and supersedes any and all prior
     agreements and understandings, written or oral, relating to such subject
     matter.

            11.7.  INTERPRETATION AND RULES OF CONSTRUCTION. Definitions
     contained in this Agreement apply to singular as well as the plural forms
     of such terms and to the masculine as well as to the feminine and neuter
     genders of such terms. Words in the singular shall be held to include the
     plural and vice versa, and words of one gender shall be held to include the
     other gender as the context requires. The terms "hereof," "herein,"
     "hereby" and "herewith" and words of similar import shall, unless otherwise
     stated, be construed to refer to this Agreement as a whole and not to any
     particular provision of this Agreement. The terms "includes" and the word
     "including" and words of similar import shall be deemed to be followed by
     the words "without limitation." Section and paragraph references are to the
     Sections and paragraphs of this Agreement unless otherwise specified. The
     word "or" shall not be exclusive. For purposes of this Agreement, the terms
     "Company" and "Subsidiary" shall include any entity which is, in whole or
     in part, a predecessor of the Company or any Subsidiary, unless the context
     expressly requires otherwise. The headings in this Agreement are included
     for convenience only and shall be ignored in the construction or
     interpretation hereof.

            11.8.  SEVERABILITY. The invalidity or unenforceability of any
     provision of this Agreement shall not affect the validity or enforceability
     of any other provision of this Agreement.

            11.9.  SPECIFIC PERFORMANCE. In addition to any and all other
     remedies that may be available at law in the event of any breach of this
     Agreement, each Investor shall be entitled to specific performance of the
     agreements and obligations of the Company hereunder and to such other

29
<Page>

     injunctive or other equitable relief as may be granted by a court of
     competent jurisdiction.

30
<Page>

     IN WITNESS WHEREOF, the parties hereto have caused this Investor Rights
Agreement to be duly executed by their respective authorized signatories as of
the date first written above.


                         ASPEN TECHNOLOGY, INC.


                         By:
                            -----------------------------------------------
                               Name:
                                    ---------------------------------------
                               Title:
                                     --------------------------------------

                         ADDRESS FOR NOTICES:
                         Aspen Technology, Inc.
                         Ten Canal Park
                         Cambridge, Massachusetts 02141
                         Attention: Chief Financial Officer and General Counsel
                         Facsimile: 617.949.1717

                         WITH A COPY TO:
                         Hale and Dorr LLP
                         60 State Street
                         Boston, Massachusetts 02109
                         Attention: Mark L. Johnson
                         Facsimile: 617.526.5000

                     [INVESTOR SIGNATURE PAGES FOLLOW]

31
<Page>

                         SERIES D-1 INVESTORS:


                         ADVENT ENERGY II LIMITED PARTNERSHIP

                         ADVENT PGGM GLOBAL LIMITED PARTNERSHIP

                         DIGITAL MEDIA & COMMUNICATIONS III LIMITED PARTNERSHIP

                         DIGITAL MEDIA & COMMUNICATIONS III-A LIMITED
                         PARTNERSHIP

                         DIGITAL MEDIA & COMMUNICATIONS III-B LIMITED
                         PARTNERSHIP

                         DIGITAL MEDIA & COMMUNICATIONS III-C
                         LIMITED PARTNERSHIP

                         DIGITAL MEDIA & COMMUNICATIONS III-D C.V.

                         DIGITAL MEDIA & COMMUNICATIONS III-E C.V.

                         GLOBAL PRIVATE EQUITY III LIMITED PARTNERSHIP

                         GLOBAL PRIVATE EQUITY IV LIMITED PARTNERSHIP

                         GPE IV CPP INVESTMENT BOARD CO-INVESTMENT LIMITED
                         PARTNERSHIP


                         By: Advent International Limited Partnership, General
                             Partner

                         By: Advent International Corporation, General Partner


                         By:
                             -------------------------------------
                             Senior Vice President

<Page>

                         ADDRESS FOR NOTICES:
                         c/o Advent International Corporation
                         75 State Street
                         Boston, Massachusetts 02109
                         Attention: Douglas A. Kingsley, Managing Director
                         Facsimile: 617.951.0568

                         WITH A COPY TO:
                         Pepper Hamilton LLP
                         3000 Two Logan Square
                         18th and Arch Streets
                         Philadelphia, Pennsylvania 19103
                         Attention: Julia D. Corelli
                         Facsimile: 215.981.4750

<Page>

                         ADVENT PARTNERS (NA) GPE III LIMITED PARTNERSHIP

                         ADVENT PARTNERS DMC III LIMITED PARTNERSHIP

                         ADVENT PARTNERS GPE-III LIMITED PARTNERSHIP

                         ADVENT PARTNERS GPE-IV LIMITED PARTNERSHIP

                         ADVENT PARTNERS II LIMITED PARTNERSHIP


                         By: Advent International Corporation, General Partner


                         By:
                             -------------------------------

                             Senior Vice President


                         ADDRESS FOR NOTICES:
                         c/o Advent International Corporation
                         75 State Street
                         Boston, Massachusetts 02109
                         Attention: Douglas A. Kingsley, Managing Director
                         Facsimile: 617.951.0568

                         WITH A COPY TO:
                         Pepper Hamilton LLP
                         3000 Two Logan Square
                         18th and Arch Streets
                         Philadelphia, Pennsylvania 19103
                         Attention: Julia D. Corelli
                         Facsimile: 215.981.4750

<Page>

                         SERIES D-2 INVESTORS:

                         PINE RIDGE FINANCIAL INC.


                         By:
                            ---------------------------------
                         Name:
                              -------------------------------
                         Title:
                               ------------------------------

                         ADDRESS FOR NOTICES:
                         Pine Ridge Financial Inc.
                         c/o Cavallo Capital Corp.
                         660 Madison Avenue
                         New York, NY  10022
                         Attention: Avi Vigder
                         Telephone: 212.651.9000
                         Facsimile: 212.651.9010

                         WITH A COPY TO:
                         Proskauer Rose LLP
                         1585 Broadway
                         New York, NY  10036-8299
                         Attention: Adam J. Kansler, Esq.
                         Facsimile: 212.969.2900

<Page>

                         SMITHFIELD FIDUCIARY LLC


                         By:
                            --------------------------------
                         Name:
                              ------------------------------
                         Title:
                               -----------------------------

                         ADDRESS FOR NOTICES:
                         Smithfield Fiduciary LLC
                         c/o Highbridge Capital Management, LLC
                         9 West 57th Street, 27th Floor
                         New York, NY  10019
                         Attention: Ari J. Storch / Adam J. Chill
                         Facsimile: 212.751.0755

                         WITH A COPY TO:
                         Schulte Roth & Zabel LLP
                         919 Third Avenue
                         New York, NY 10022
                         Attn: Eleazer Klein, Esq.
                         Facsimile: 212.593.5955

<Page>

                         PERSEVERANCE LLC


                         By:
                            ---------------------------------
                         Name:
                              -------------------------------
                         Title:
                               ------------------------------

                         ADDRESS FOR NOTICES:
                         Perseverance LLC
                         c/o Cavallo Capital Corp.
                         660 Madison Avenue
                         New York, NY  10022
                         Attention: Avi Vigder
                         Facsimile: 212.651.9010

                         WITH A COPY TO:
                         Proskauer Rose LLP
                         1585 Broadway
                         New York, NY  10036-8299
                         Attention: Adam J. Kansler, Esq.
                         Facsimile: 212.969.2900

<Page>

                                                                         ANNEX A

                              PLAN OF DISTRIBUTION

     The selling stockholders may, from time to time, sell any or all of their
shares of common stock on any stock exchange, market or trading facility on
which the shares are traded or in private transactions. These sales may be at
fixed or negotiated prices. The selling stockholders may use any one or more of
the following methods when selling shares:

     -    ordinary brokerage transactions and transactions in which the
          broker-dealer solicits purchasers;

     -    block trades in which the broker-dealer will attempt to sell the
          shares as agent but may position and resell a portion of the block as
          principal to facilitate the transaction;

     -    purchases by a broker-dealer as principal and resale by the
          broker-dealer for its account;

     -    an exchange distribution in accordance with the rules of the
          applicable exchange;

     -    privately negotiated transactions;

     -    short sales;

     -    broker-dealers may agree with the selling stockholders to sell a
          specified number of such shares at a stipulated price per share;

     -    a combination of any such methods of sale; and

     -    any other method permitted pursuant to applicable law.

     The selling stockholders may also sell shares under Rule 144 under the
Securities Act, if available, rather than under this prospectus.

     The selling stockholders may also engage in short sales against the box,
puts and calls and other transactions in our securities or derivatives of our
securities and may sell or deliver shares in connection with these trades.

     Broker-dealers engaged by the selling stockholders may arrange for other
brokers-dealers to participate in sales. Broker-dealers may receive commissions
or discounts from the selling stockholders (or, if any broker-dealer acts as
agent for the purchaser of shares, from the purchaser) in amounts to be
negotiated. The selling stockholders do not expect these commissions and
discounts to exceed what is customary in the types of transactions involved. Any
profits on the resale of shares of common stock by a broker-dealer acting as
principal might be deemed to be underwriting discounts or commissions under the
Securities Act. Discounts, concessions, commissions and similar selling
expenses, if any, attributable to the sale of shares will be borne by a selling
stockholder. The selling stockholders may agree to indemnify any agent, dealer
or broker-dealer that participates in transactions involving sales of the shares
if liabilities are imposed on that person under the Securities Act.

     The selling stockholders may from time to time pledge or grant a security
interest in some or all of the shares of common stock owned by them and, if they
default in the performance of their secured obligations, the pledgees or secured
parties may offer and sell the shares of common stock from time to time under
this prospectus after we have filed an amendment to this prospectus under Rule
424(b)(3) or other applicable provision of the Securities Act amending the list
of selling stockholders to include the

                                      A-1
<Page>

pledgee, transferee or other successors in interest as selling stockholders
under this prospectus.

     The selling stockholders also may transfer the shares of common stock in
other circumstances, in which case the transferees, pledgees or other successors
in interest will be the selling beneficial owners for purposes of this
prospectus and may sell the shares of common stock from time to time under this
prospectus after we have filed an amendment to this prospectus under Rule
424(b)(3) or other applicable provision of the Securities Act amending the list
of selling stockholders to include the pledgee, transferee or other successors
in interest as selling stockholders under this prospectus.

     The selling stockholders and any broker-dealers or agents that are involved
in selling the shares of common stock may be deemed to be "underwriters" within
the meaning of the Securities Act in connection with such sales. In such event,
any commissions received by such broker-dealers or agents and any profit on the
resale of the shares of common stock purchased by them may be deemed to be
underwriting commissions or discounts under the Securities Act.

     We are required to pay certain fees and expenses incident to the
registration of the shares of common stock, including certain fees and
disbursements of counsel to the selling stockholders. We have agreed to
indemnify the selling stockholders against certain losses, claims, damages and
liabilities, including liabilities under the Securities Act.

     The selling stockholders have advised us that they have not entered into
any agreements, understandings or arrangements with any underwriters or
broker-dealers regarding the sale of their shares of common stock, nor is there
an underwriter or coordinating broker acting in connection with a proposed sale
of shares of common stock by any selling stockholder. If we are notified by any
selling stockholder that any material arrangement has been entered into with a
broker-dealer for the sale of shares of common stock, if required, we will file
a supplement to this prospectus. If the selling stockholders use this prospectus
for any sale of the shares of common stock, they will be subject to the
prospectus delivery requirements of the Securities Act.

     The anti-manipulation rules of Regulation M under the Securities Exchange
Act may apply to sales of our common stock and activities of the selling
stockholders.

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