Penumbra Overture Won't Run on ATI Mobility HD2600 512 Mb

[Nephil]

Hello,

I have a problem: Penumbra starts, changes screen resolution to a lower one, the screen goes black, a second later it exits and displays a message saying that my graphics card doesn't support vertex shaders.

I have an Asus notebook with the following config:

AMD Athlon X2 1.8 Ghz
1 GB of RAM
ATI HD2600 Mobility w. 512 Mb of on-board memory

I installed the patch but it won't do any good.

Please help.