The error occurred again today and I was able to get a bug-report. I put it here: http://www-und.ida.liu.se/~tholi945/...bug-report.log
the /var/log/messages looks worse than it is. I got this card a year ago. All the other Xid are from the old card. The Xorg.conf is a little messy but I use the geforce card for my primary screen and a voodoo3 for an other screen running in xinerama.