DotNet 2.0 Program on ReactOS 0.4.4 does not start properly

I have a program in DotNet 2.0 (programmed by myself, so I could add log output if required) that fails to start properly. It starts, it writes some logs (so the runtime seems to be installed correctly), but it does not show the program window. It just quits, process is not existing in the taskmanager.

The problem seems to be located somewhere here:
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
FormMy runForm = new FormMy();
Application.Run(runForm);
(I am not sure if that helps much, since this is pretty much the start of the program)

Is there a know issue with DotNet 2.0? Anything I could do?

Thanks for your help in advance!