Uhmm, I encoutered the same issue with SharePoint. Take a look at this article:
http://technet.microsoft.com/en-us/library/aa996091.aspx
It shows how to switch IIS from 32 to 64-bit mode


>This entry might go under several categories, but I thought this one was as good as any. I am installing SQL 2005 Ent. on 64 bit server with Windows Server 2003. I have installed .net framework 3.0 with SP1. During the set-up check procedures, SQL installer tells me that I need to install .asp (which is part of the .net framework) for 32 bit machine. I have not been able to discover how to do that. I have installed the .net framework, but there are no options to do anything else.
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>SLQ installer will not allow the installation of Reporting Services with out this corrected.
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>Your help is greatly appreciated.
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>Since I first wrote this I was finally able to locate the solution. In case anyone is interested, it can be found at:
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>http://msdn.microsoft.com/en-us/library/bb677367(SQL.90).aspx
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>Thank you for your patience. I will try to look more before posting next time. :)