Tonight I ran into a problem running the start of a composite application that I was making work with the Infragistics support for the Composite UI application block. The problem occurred with the simplist implementation of an empty shell form. The exception was a configuration exception that said, "Configuration system failed to initialize" and it had an inner exception with the message, "Unrecognized configuration section userSettings..."
I let Visual Studio create a Settings class and add the configuration information to the App.Config (before this point I didn't have one), but the same problem occurred. Investigating the exception further I dug down into where it was pulling the configuration information. It was grabbing settings from within the user application data folder. In there was a configuration file that contained a toolbars layout file from a prototype that had a ToolbarsManager instance.
I deleted the file and rebuilt the project and it ran fine. Hopefully, this will help someone else out that gets a similar exception.