hmm,
strange problem.
I use Mandrake 9.2 and a Radeon 8500 with the 3.2.8 driver by Ati.
3D works in evry other prog... Wine/WineX, Tuxracer :), UT2004 Demo, GLXgears, ePSXe, etc.
but not in mupen64, i dont depend on the GFX plugin, cause it happens with every one.. (loaded also the newest)...