I have had copious amounts of days with experience in getting ATI Cards/Drivers to work.. (Don't get excited yet hehe, I have yet to be completely successful with my own!) However in reading this thread, you posted:
display: :0.0 screen: 0
OpenGL vendor string: Mesa project: www.mesa3d.org
OpenGL renderer string: Mesa GLX Indirect
OpenGL version string: 1.3 Mesa 4.0.4
I was told by documentation, that if the output of fglrxinfo had the line Indirect, direct rendering was not enabled succesfully ='( I know that isn't exactly your problem, but I just wanted to bring that to your attention in case it might be responsible for part of it. Also, in "many" how-to's etc.. I read that for many Radeon cards, we have to have AGPGART enabled. Mine personally gives me a no device found error, so I have to insmod it with the try_unsupported bit. I have found "Many" links to getting things to work right each a little different.. but here are some that hopefully help you.
Try This Forum As Well
Hope those help!, And by all means if you figure out please post the solution, it may save the life of a video card that has found its way onto a hit list in my pocket >=)