Asp.net Server error

Open up the Visual Studio Command Prompt (should be in the Visual Studio.NET Program Group) and type this in:
aspnet_regiis.exe -i
OR
C:\windows\Microsoft.NET\Framework\v1.1.4322\aspnet_regiis.exe /i

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To fix IIS mappings for ASP.NET, run the Aspnet_regiis.exe utility:1. Click Start, and then click Run.
2. In the Open text box, type cmd, and then press ENTER.
3. At the command prompt, type the following, and then press ENTER:
"%windir%\Microsoft.NET\Framework\version\aspnet_regiis.exe" -i