The same problem for me. After upgrade from Dapper Drake to Edgy Eft (Release) instead of screen saver blank screen is shown.
Following lines in .xsession-errors file: gnome-screensaver-Message: Found best visual for GL: 0x21 gnome-screensaver-Message: Found best visual for GL: 0x21 gnome-screensaver-Message: Found best visual for GL: 0x21 Attached xorg.conf ** Attachment added: "xorg.conf" http://librarian.launchpad.net/4945674/xorg.conf -- Screen saver showing blank screen https://launchpad.net/bugs/65810 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs