I can start the game just fine but when the actual game screen loads, the NPCs and main character flash in and out, and the game is basically frozen.
Windows 7 RC1 x64
Geforce GTX275 896mb
AMD Phenom II X4 940
4gb of ram
and yes, all the drivers are fully up to date. I installed DX9 as well and tried compatibility modes for the game.
Edit: Looks like this topic [url=]http://www.gog.com/en/forum/gothic_series/game_crashes_when_going_outside[/url] is actually about the same issue. Sadly no solutions yet. :(
Anyone try using the Virtual PC and XP Mode thing yet?

XP mode won't work in virtual pc as theres no support for direct3d8.
However, vmware workstation might work. Anyway you shouldn't be using pre rtm os's :P
I suppose you could try setting uac as low as possible and disable aero and see if that helps.
Gothic 2 works fine on my vista x86_64 pc.

If you plan on keeping win7 you might give VirtualBox a try. Version 3 is in beta, and it has direct3d and opengl 2.0 support.