How can I do to install the proprietary driver ATI FireGL that I download from ATI website?
I guess you need to have sources of the kernel installed, then become root, then switch runlevel to 3 (telinit 3 or init 3), then run the installer (bash ati-driver-installer*.run) and follow what it says to you. If you succeed fgl_glxgears should work.
Good luck during this dirty work
To tell the truth I have an ATI card too but I don`t use their driver. I replaced "vesa" with "ati" in xorg.conf and it works fine without all this commotion. But if you really need 3D acceleration you have to try.