Problem: IIS was installed on the Responder web server after the .NET Framework. To avoid this problem, when initially setting up the web server, make sure to install IIS followed by .NET Framework.

Fix: To correct the problem, it is NOT necessary to uninstall IIS and .NET Framework. Open a command prompt, and browse to C:\WINDOWS\Microsoft.NET\Framework\v1.1.4322. Enter the following at the command prompt.

        aspnet_regiis.exe -i

If the problem persists, open a command prompt and browse to C:\WINDOWS\Microsoft.NET\Framework\v1.1.4322. Register the file aspnet_isapi.dll by entering the following at the command prompt.

    regsvr32 aspnet_isapi.dll