Hey, thank you all.
It helps to know that I am not alone

@frazzle: I use Windows XP edit: äh sorry I've red os I'am not so good in this shortcuts sorry I don't understand OP and atm <shame>
processor: AMD 3700+ 1GB ddr1 ram

@vadim647: I tried and tried, but until now I wasn't able to reproduce the error I will test your solution if the error apears again.

@nems: That's possible, but i've never experienced that problem with A6. I wonder if there is a way to reset the hole directx/driver or what ever

@helghast: It's possible to. But I wasn't able to reproduce the error with this "method" If it is an engine problem, there must be a way to reset the engine.

Thanks for replies.

@vanste:
Do you use a script? Which operatingsystem you are using?
Check your DirectX version (it has to be 9) with the dxdiag (execute -> dxdiag)