I have several forms in a C# application. I use Visual Studio 2010 Beta, but .NET 3.5 and C# 3.
I have a base form, called FilteredQueryViewForm in the Shd namespace
I had a similar issue with a different exception related to code in my base form's _Load method, so none of the solutions helped me. There was an exception in design-time that doesn't happen in run-time (null value referring to a static instance of another class). My solution was to throw a try-catch block around all of the code in that method.