I have a feeling that your application is not using the latest generated code. Make sure you reference the newly generated code, and that you reference the latest ORMSupport dlls (which should also match the version used in the V.S. toolbox => "Choose Items")
I've closed this thread as there are multiple threads with the same topic from the same user, so we'll concentrate on the typedlist issue in the typedlist thread as that's related. (for the record, no we can't reproduce the problem).