Fixing "Configuration System Failed to Initalize" Exception
If you see the "Configuration System Failed to Initialize" exception at run time, it is typically caused by an invalid entry in your app.config or web.config file. In my case, I encountered this exception when I had an "<add key...>" element out of place. Oddly enough, the compiler didn't warn me about this when I rebuilt my solution with the config file open (as it usually does with most other config file errors).
Microsoft .NET MVP 2002-2009
Chief Architect, MM .NET Application Framework