@TechMuc: Thanks a lot for these function, didn't know them. I couldn't find another memory leak using them. Also, after a restart of my computer resolution switching now works for me without a crash... very strange
Anyway, the memory corruption that caused a crash before was within the engine (not necessarily the engines fault though), so the CRT debug settings wouldn't affect it afaik.

Also, I can't reproduce any problem with the registration. What exactly happend? You clicked the OK button and got an error message? Can you reproduce that?

@lostclimate:
The game doesn't use OpenGL, I don't see any console output that says otherwise. It uses Acknex as engine, only the game logic and networking system are custom written and independent of acknex. The dynamic shadows eat a lot of performance, so it probably can't run well on a virtual graphics card.
Thank you for testing it though!