I have the same problem, and have not resolved it. I do have some information to share with you though. The libGL.so.1 => /usr/X11R6/lib/libGL.so.1 (0x40016000) entry from the ldd refers to a symbolic link. Check it out.
scarter]$ ls -l /usr/X11R6/lib/libGL.so.1
lrwxrwxrwx 1 root root 27 Sep 12 22:46 /usr/X11R6/lib/libGL.so.1 -> /usr/X11R6/lib/libGL.so.1.2
So this file is exactly what the ATI doc says is good to have. But I also get
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'll keep you updated on what I find out.