I am not sure if this is the right place but..

[Skaruts]

Or maybe your graphic card doesn't support the highest resolution in the game. Try the one below the highest or try to raise it gradually.

you have several degrees, being the most common
(It's the number of pixels in the screen: Width x Height)
640x400
640x480
800x600
1024x768
1248x960
1248x1024
(There are many more not listed here)

I once had a graphics card that, despite it's quality, didn't support anything above 800x600, and some error like that one appeared whenever I tryed to play at 1024x768 or higher.

But try something with the shaders like Thomas said and the latest drivers. That may be the problem/solution after all.