Maybe just some stupid bugs that i cant see but heres the problem:
On ubuntu 8.04 (tested with mesa and ati official drivers):
When I draw png images with alpha (transclusent(?) images),
it will become darker than on xp.
Look at the picture I uploaded.
And second problem, on ubuntu, when I update lights position,
scene flickers. These works fine on xp.
In the zip file you can find sources, images and Release .exe.