Today I have beed cursing VS2005 for it’s stupidity and lack of error descriptions, it showed me a very informative message box:
An unexpected error has occured.
Object reference not set to an instance of an object.
… they could added a nice icon of „the finger”.
I tryed to change a DataSource property n BindingSource at design time. Aparently VS needs at least one class to be placed in the root of the project.
Anyway thanks to Kjell-Sverre for the tip.