The problem is, that the wineprefix has to be a certain one with installed programs. When another user logs in, a new wineprefix /home/user/.wine is created. But this wineprefix is pristine, and does not contain the installed Windows programms. That is why i tried the way of overwriting the users wineprefix with the individual wineprefix (That I store in /opt/samplewineprefix/)
