It's strange because it's in the xscreensaver backend but i suppose you're using gnome-screensaver. Don't you?
Do you have any error message in the console when the plugin is loaded? -- When running xchat-gnome I'm flooded by crash message https://launchpad.net/bugs/56362 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
