AMD APU problems

[EXODY/ZERO]

So, I got Amnesia on Steam through the Humble Indie Bundle V. Before, I had the AMD Radeon HD4850 which worked perfectly well with Amnesia. My GPU failed, so I bought a new PC with the AMD A8 5600K at its core, acting as the sole GPU in the PC. The problem is, that I simply can't start Amnesia, it always fails displaying an error:

"Amnsesia.exe has caused an EXEPTION_ACCESS_VOILATION"

I have all the latest MBO and CPU/GPU drivers installed, and the APU is more than capable to run the game.

Please help!

Setup:
Windows 8 Pro x64
CPU/GPU: AMD A8 5600K
RAM: 8GB 1600MHz DDR3