We've had some problems with the Binding Source component in our Windows Forms development and I wanted to jot down a note on here in case anyone else comes across this.
The problem we were having was an IDE runtime error which looks like a NullReferenceException, the specific message says "Object reference not set to an instance of an object".
Apparently this has something to do with the .datasource files that are auto-generated by visual studio for holding "default" values. You can remove these from the My Project folder and then the error goes away. Not sure why these are even required since you can still build without them.