For others having trouble here with ATI Radeon, here is how I got it working on MEPIS 8.5 Sid KDE 4.5 64-bit (per Danum's install):
- In root console, run smxi to install liquorix kernel 2.6.33-5.dmz.2-liquorix-amd64
- Boot into the new kernel...add "2" in the Grub line interactively to put you into Runlevel 2...otherwise you'll have trouble getting to root login console (at least I did)
- In root console, run sgfxi -o 10-4 to override the default ATI driver install for 10-9 and use 10-4
- Turn on Compositing...change Compositing type from "XRender" to "OpenGL"
BTW, H2 clearly states in the sgfxi notes that only liquorix kernels 2.6.32 and 2.6.33, work with XOrg 7.5, and then only with ATI driver 10-4
...but I neglected to read it carefully.