Strange graphical bugs (video included)

[undying]

I have the same bug with textures like i do in penumbra overture. They seem to change when light hits them or when i move my sight. I have an ati hd 2600 pro. Latest drivers. Still this bug. I disabled catalyst a.i. and post effects and still there is no improvement. Is there anything that can be done to correct this. i have catalyst 8.1.

I've uploaded a youtube video here http://www.youtube.com/watch?v=OFDZDmCrMFU

My system is :

CPU Pentium D 820 @ 2.8 GHz
Motherboard AsRock 775 Dual-Vsta
Memory 2 x 512 DDR2 Kingston @ 667MHz
VGA Ati HD 2600 Pro 256mb DDR3 @ 600/1400 MHz
Sound Creative Audigy Player

Will you fix this problem for the full version of the game ?