Ok, I've browsed through many, many sites who have people stating they cannot get the console to work in Vista, and by extension windows 7. The problem isn't the game, or a Driver, or even Vista. It's a combination of the Game and Vista.
I'll explain. Vista uses the User Account Control. This forces you to do certain things as an Administrator. For the programs and games that really don't need to run as Admin, Vista creates a VirtualStore. This is a location you, the user, can read and write files to. This is what happened with Gothic 3 in Vista.
For get around the problem of not having access to the console, Press the Windows Key on your keyboard. Hold that and press R. This will bring up the RUN box. COPY and PASTE the following INCLUDING THE QUOTES into the RUN box. Press enter.
The copy/paste option failed to turn up a file location. I hunted down the location, following your file directory. There was no Aspyr file in the programs folder, other games were listed but not Aspyr.
I did a search and did find in c\program files\aspyr\gothic III\ I did find several .ini files, but none of them had test mode listed in them.