On operating systems before Windows 2008, this error can indicate that the .NET Framework is not registered with IIS. The .NET Framework detects which versions of IIS exist when the .NET Framework is installed, and it automatically registers itself with IIS. If IIS does not exist when .NET Framework is installed, the .NET Framework is not registered with IIS. Reinstalling IIS after the .NET Framework has been installed does not help.
If you receive this error, run the ASP.NET IIS Registration Tool, a program that comes packaged with the .NET Framework, to register it with IIS. Refer to AdHoc Properties Missing ASP.NET Tab for details.
Below is an example of an error caused by .NET Framework not being registered with IIS:
