When you setup your machine to handle asp.net you have to run a command prompt to register and get it working. This article contains the command line that you use to get asp.net working on your IIS installation:
http://www.microsoft.com/technet/prodtechnol/WindowsServer2003/Library/IIS/187d0e2c-8e89-49ad-a89d-e26e4d76ee68.mspx?mfr=true
Shiraz Cupala / Microsoft InfoPath MVPQdabra® Software / Streamline data gathering to turn process into knowledge