<Page>
Exhibit 10.124
POST CLOSING AGREEMENT
THIS POST CLOSING AGREEMENT (this Agreement@) is made and entered into as
of the 28th day of April, 2004, by and between INLAND WESTERN SAN ANTONIO
MILITARY DRIVE LIMITED PARTNERSHIP, an Illinois limited partnership
("Purchaser"), and XXL ONE, LTD., a Texas limited partnership ("Seller"), in
connection with the acquisition by Purchaser of that certain property commonly
known as Alison's Corner Shopping Center, San Antonio, Texas (the AProperty@).
WHEREAS, Purchaser is acquiring the Property from Seller (the
"Transaction").
WHEREAS, in order to proceed with and consummate such acquisition and as a
condition to closing the Transaction, Purchaser requires that Seller agree to
the obligations set forth below, which are to be performed after such closing.
NOW, THEREFORE, for good and valuable consideration including the mutual
promises contained herein, the parties hereto agree as follows:
1. WARRANTIES. Seller's right, title and interest in, to and under the
warranties set forth on Exhibit A attached hereto and made a part hereof
(individually, a "Warranty", and collectively, the "Warranties") were not
assigned to Purchaser at the closing of the Transaction because such Warranties
may not be assigned or transferred without the prior consent of the Warranty
issuer. From and after the date of this Agreement, Seller shall use its best
efforts to obtain the aforementioned consents (upon the receipt of which Seller
shall assign such Warranty to Purchaser) or have the Warranties reissued in the
name of Purchaser. Seller shall be responsible for the payment of any and all
fees and costs in connection with obtaining any such consents or the reissuance
of any of the Warranties. Seller shall, until the first to occur of (i) the
expiration of an applicable Warranty and (ii) the date that the applicable
Warranty is assigned to Purchaser (with any and all required consents) or
reissued in the name of Purchaser, cooperate with Purchaser, at no cost to
Seller, with respect to the enforcement of the terms and provisions of, and any
and all claims under, any Warranty.
2. FURTHER ASSURANCES. Seller and Purchaser agree to cooperate with each
other following the closing to confirm any matter and execute any document
reasonably required by the other party in furthering of the closing.
3. MISCELLANEOUS. This Agreement shall be interpreted and enforced in
accordance with the internal laws of the State of Texas. The invalidity or
unenforceability of any provision of this Agreement shall not affect, modify or
impair the validity and enforceability of all other provisions of this
Agreement. This Agreement shall be binding on and shall inure to the benefit of
the parties hereto and their representatives, heirs, legatees, successors, and
assigns; provided, however, that Seller shall have no right whatsoever to assign
its interest under this Agreement and any such attempted assignment shall
automatically be null and void and of no force and effect, and shall be deemed a
breach by Seller of its obligations hereunder. No failure or delay by Purchaser
in exercising any right, power or privilege under this Agreement shall operate
as a
<Page>
waiver thereof, nor shall any single or partial exercise thereof preclude any
other or further exercise thereof or the exercise of any right, power or
privilege hereunder. No change, amendment or modification of this Agreement
shall be binding or enforceable unless in writing and executed by the party to
be bound thereby. The covenants, agreements and indemnification provisions
contained in this Agreement shall be enforceable notwithstanding the closing of
the Transaction. In the event of litigation with respect to any portions of this
Agreement, the prevailing party will be entitled to collect all reasonable legal
fees incurred in connection with such litigation from the non-prevailing party.
Purchaser shall have all remedies available at law and in equity on account of a
default by Seller under this Agreement. Time is of the essence of this Agreement
and the terms hereof. This Agreement may be signed in counterparts.
[SIGNATURES ON FOLLOWING PAGE]
<Page>
IN WITNESS WHEREOF, the parties have executed this Post Closing and
Indemnity Agreement effective as of the first date written above.
SELLER:
XXL ONE, LTD., a Texas limited partnership
By: DEVELOPMENT STRATEGIES TEXAS, INC. its General
Partner
By: /s/ David W. Monnich
------------------------------------
David W. Monnich
President
PURCHASER:
INLAND WESTERN SAN ANTONIO MILITARY
DRIVE LIMITED PARTNERSHIP, an Illinois limited
partnership
By: INLAND WESTERN SAN ANTONIO MILITARY DRIVE GP,
L.L.C., its General Partner
By: INLAND WESTERN RETAIL REAL ESTATE TRUST,
INC., its Sole Member
By:
--------------------------------
Name:
-------------------------
Its:
--------------------------
3
<Page>
IN WITNESS WHEREOF, the parties have executed this Post Closing and
Indemnity Agreement effective as of the first date written above.
SELLER:
XXL ONE, LTD., a Texas limited partnership
By: DEVELOPMENT STRATEGIES TEXAS, INC., its General
Partner
By:
------------------------------------
David W. Monnich
President
PURCHASER:
INLAND WESTERN SAN ANTONIO MILITARY
DRIVE LIMITED PARTNERSHIP, an Illinois limited
partnership
By: INLAND WESTERN SAN ANTONIO MILITARY DRIVE GP,
L.L.C., its General Partner
By: INLAND WESTERN RETAIL REAL ESTATE TRUST,
INC., its Sole Member
By: /s/ Valerie Medina
--------------------------------
Name: Valerie Medina
-------------------------
Its: Asst Secretary
--------------------------
3
<Page>
EXHIBIT A
WARRANTIES
<Table>
<Caption>
WARRANTY PROVIDER CONSENT EXPIRATION
- -------------------------- ------------------------ ----------------- ----------
ROOF (595 SQS) American Roofing & Metal NEED CONSENT 6/9/05
Co., Inc.
ROOF (59,500 sq.ft.) OMNOVA Solutions, Inc. NEED CONSENT 5/28/2018
Unit Model No. LGA180HL2G, Lennox NEED CONSENT FOR Varies
Serial No. 5603D05436 ASSIGNMENT OF THE
EXTENDED WARRANTY
Unit Model No. LGC156HL1G, Lennox NEED CONSENT FOR Varies
Serial No. 5603D05461 ASSIGNMENT OF THE
EXTENDED WARRANTY
Unit Model No. LGA210HL2G, Lennox NEED CONSENT FOR Varies
Serial No. 5603D05465 ASSIGNMENT OF THE
EXTENDED WARRANTY
Unit Model No. LGA102HS3G, Lennox NEED CONSENT FOR Varies
Serial No. 5603C04950 ASSIGNMENT OF THE
EXTENDED WARRANTY
Unit Model No. LGA120HS2G, Lennox NEED CONSENT FOR Varies
Serial No. 5603D05639 ASSIGNMENT OF THE
EXTENDED WARRANTY
Unit Model No. LGA042HS2G, Lennox NEED CONSENT FOR Varies
Serial No. 5603D05848 ASSIGNMENT OF THE
EXTENDED WARRANTY
Unit Model No. LGA060HS2G, Lennox NEED CONSENT FOR Varies
Serial No. 5603D05822 ASSIGNMENT OF THE
EXTENDED WARRANTY
</Table>
4