First, on a 64 bit XP box, the Wizard Framework dlls can get lost and not in the GAC after the SDK for vista is installed. The following link
http://www.codeplex.com/DocProject/Thread/View.aspx?ThreadId=9037 will walk someone through the solution.
Second, when starting up my first Powershell project, the designer for the PSSnapin.cs had the following complaint:
Hope this is useful.