I often run into this error message for various reasons like doing a reinstallation, machine upgrade or preparing a workstation for a new co-worker...
This error is fairly simple to fix but if you don't know how, it could drive one crazy. You often run into this error after you install Visual Studio 2005 and then try to run a webpage on your machine. The error you encounter will read something like this:
Failed to access IIS metabase.
If so, you may have installed IIS after the .NET framework has been installed. To fix this, try to repair your ASP.NET installation and set up all of the appropriate ISAPI extension mappings using the aspnet_regiss utility in the .NET framework folder.
This utility is found in the .NET framework version number under your Windows installation folder.