I have the same problem - lock screen no longer works since upgrading from Dapper to Edgy. AFAICT my hardware (ATi Mobility Radeon X1300) doesn't support Option "VideoOverlay" "on" with the fglrx drivers packaged with Edgy (it won't do acceleration when you have it on). So I can't use that solution.
-- Lock Screen not working anymore https://launchpad.net/bugs/68123 -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs