http://bugs.winehq.org/show_bug.cgi?id=20236
--- Comment #14 from Stefan Dösinger stefandoesinger@gmx.at 2010-05-17 13:51:40 --- Still the same exception? I guess in this case it would be helpful to find failing shader and ask the Mesa developers for their opinion. However, from the log I guess that this isn't an easy job - I think there are 5 different shaders(not many), but all of them are successfully used at least once, so I guess is is some other aspect of the GL config that causes the issue.
Maybe try to file a Mesa bug stating your exact configuration, the failing assertion, and a link to a game demo. It is likely that they'll say that they can't look at the Windows app and need some stand-alone testcase, in which case I can try to assist with more debugging(I don't have this card, so it will be tricky). However, maybe they know what's wrong from the assertion alone.