Try running it in 16bit mode. I had a similar problem and that fixed it. You also need to check if the video bios handles 1280x800 too -- This is an email sent via the webforum on http://fcp.homelinux.org http://fcp.homelinux.org/modules/newbb/viewtopic.php?post_id=83604&topic_id=18254&forum=28#forumpost83604
