Comment 9 for bug 740767

I have a similar problem:

in dmesg:
[ 543.093184] do_general_protection: 42 callbacks suppressed
[ 543.093188] compiz[5601] general protection ip:7faa31063394 sp:7fff7e2bdf30 error:0 in libpthread-2.13.so[7faa3105a000+18000]

video card:
VGA compatible controller: Intel Corporation 82G33/G31 Express Integrated Graphics Controller (rev 02)

Before upgrading to 11.04 (from 10.10) never had an issue related to 3d.

Basically unity and gnome (ubuntu classic) does not have a window decorator and cant start one.

On ubuntu classic (no effects) works fine.

Also, under kde everything is extremely slow until special effects are switched off (ALT SHIFT F12).