This happens with me too, but it seems only with GL or 3d themes/hacks. If I'm logged in with ssh, killing the process (gnome-screensaver and hack process) or restarting X makes no difference. Shutdown fails too. No further ssh logins can be made.
Have done dist-upgrade. Video card: SiS 305. D -- Screensaver freezes on Dapper (ATI Radeon 8500 LE) https://launchpad.net/malone/bugs/38181 -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
