EXHIBIT 24 POWER OF ATTORNEY Each person whose signature appears below or on a counterpart of this power of attorney, constitutes and appoints CURTIS A. SAMPSON and PAUL N. HANSON as his true and lawful attorneys-in-fact and agents, each acting alone, with full power of substitution and resubstitution, for him and in his name, place and stead, in any and all capacities, to sign any or all amendments to this Annual Report on Form 10-K and to file the same, with all exhibits thereto, and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, each acting alone, full power and authority to do and perform each and every act and thing requisite and necessary to be done in and about the premises, as fully to all intents and purposes as he might or could do in person, hereby ratifying and confirming all said attorneys-in-fact and agents, each acting alone, or his substitute or substitutes, may lawfully do or cause to be done by virtue thereof. Signature Title Date --------- ----- ---- /s/Curtis A. Sampson Chairman of the Board of Directors, March 29, 2005 - -------------------------- Chief Executive Officer and Director Curtis A. Sampson /s/Steven H. Sjogren President, Chief Operating Officer, March 29, 2005 - -------------------------- and Director Steven H. Sjogren /s/Paul N. Hanson Vice President, Treasurer and March 29, 2005 - -------------------------- Director Paul N. Hanson /s/Charles A. Braun Chief Financial Officer and March 29, 2005 - -------------------------- Principal Accounting Officer Charles A. Braun /s/Ronald J. Bach Director March 29, 2005 - -------------------------- Ronald J. Bach /s/James O. Ericson Director March 29, 2005 - -------------------------- James O. Ericson /s/Luella Gross Goldberg Director March 29, 2005 - -------------------------- Luella Gross Goldberg /s/Paul A. Hoff Director March 29, 2005 - -------------------------- Paul A. Hoff /s/Gerald D. Pint Director March 29, 2005 - -------------------------- Gerald D. Pint /s/Wayne E. Sampson Director March 29, 2005 - -------------------------- Wayne E. Sampson