Tried installing the latest app from WGT, and it seemed to work. Re-started the machine, and the game started after that. Changed resollution, saved and ended the game. When starting the game again (without re-starrting the PC), the foult reappeared. Ran the Delete WGT Registry Key again (without re-starrting the PC) , and the game started. I once again had to adjust the resollution.
Now it seems I can start the app several times, but I have to adjust resollution every time, even though I save the settings.
So the app needs some work, but at least I can get to it thanks to you.