Have you checked your installation of the ATI driver (fglrx)?
This is often a problem.
Make sure you have the fglrx driver installed (ATI tab in Mepis OS Center) and you also need to get the fglrx kernel module to match your kernel in synaptic from the Mepis repositories
Relevant commands in konsole as normal user:
glxinfo
glxgears -info
You should have direct rendering and OpenGL from ATI rather than Mesa (though the Mesa OpenGL works, just not as well)
You may also need to edit your xorg.conf either manually or with fglrxconfig
Post to
http://www.mepislovers.org -- great forum
Mepis Wiki
http://www.mepislovers-wiki.org
Mike