I think I have similar problem. I have two Xes on my comp - one libc5 and one libc6 (chrooted). When I run libc6 X with NVidia driver and then run libc5 X (of course without NVidia driver) cursor is damaged - sometime there are two smaller cursors around "right" position, sometime there are two smaller things around without shape of selected cursor.<BR>
I think NVidia drivers don't restore graphics cursor properly. SW reset (by running DOSemu) didn't help.