Hey thx for the reply
at first, i have a up to date 10.7.4 installed, forgot to update the profile.
In the meantime i was in the apple store. They suggested to send the MBP in for 1 up to 3 weeks for testing. After deciding this as a inacteptable solution i went to a Apple Authorized Dealer, explained and showed the same problem to them and got my Mainboard replaced in 30 Minutes for free because of Apple Care.
The Apple Authorized Dealer also told me this problem is known, some of the ATI cards are crap. But instead of talking sensless stuff, like the people in the Apple Store, they helped me.
now everything works fine.
how to Fix:
Answer: let apple switch the Mainboard
@clintonfrombirmingham: Do the black pixels (as seen on your screen shot) only show up in the Finder windows and at the same spot?
Answer: no, but primarily, but i saw them also at the screenlock window and some other windows
@adolfofromden haag: Yo can try with gfxCardStatus[1]: disable the dynamic switch videocard selector and force to use the integrated for instance just when you are using the battery.
Answer: yes, using only the integrated gfx, fixes the errors