I'm not really sure but the only thing I did was upgrading the driver. I can see no other changes in my system, deleting the Tribes 2 configuration does not help either.
T2 is quite known for crashing but it should at least attempt a switch to its graphics mode before dying.
Since I've seen the Postal 2 demo being announced here as well, I tried it and it dies with "Couldn't load OpenGL library".
Other OpenGL applications like Tuxracer or bzflag work fine. They look accelerated, but I never played them without acceleration, so I can't tell.
I would be grateful for any hints on how to solve this problem.