Comment 7 for bug 515933

Sounds like you still have xorg-edgers karmic packages installed which have higher version numbers than the lucid ones? mesa had quite a bit of restructuring in lucid (libgl is provided as an alternative and is located at /usr/lib/mesa/ now) so that will not work. Does dpkg -l | grep "~karmic" return anything? you want to make sure none of the karmic packages from xorg-edgers are remaining.