Hi Thorsten,
I have enabled DEBUGGING and got the following warnings:
Top of screen
Warning: session_start() [function.session-start]: open(C:\DOCUME~1\ADMINI~1\LOCALS~1\Temp\php\session\sess_vr6uq5hq185eorfvi0om6f2kg0, O_RDWR) failed: Permission denied (13) in C:\Inetpub\wwwroot\TCTFAQ2.0\admin ...