Amnesia from steam black box problem

[tesus]

Hi, this is the problem:

amnesia.exe caused an exception_access_violation in module amnesia.exe at 0023:004A5838

I tried 3 times to uninstall it, and download again from steam, checked files integrity, or tried to run it on different graphic settings, and nothing helped.
I even downloaded a pirate version to check if it's a steam problem, and what's most strange the pirate version works perfectly, but the one than I paid for doesn't work.
I have a Win 7 64 bit, and a Radeon 6770 with newest drivers.
I'll add a crash report, and maybe someone will know something from it.
Thanks for any response.