I have that problem too - The same black screen at start/install. ATI Radeon 9800, LG L1932TQ (19" LCD) connected via DVI. It might be a drivers issue.
-- Install 6:10 RC Failure: Black screen at Live Desktop Stage https://launchpad.net/bugs/67487 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs