Could you try pressing Ctrl-Alt-F1 and then Alt-F7 to switch away from X and back? If that lets you proceed, then it's a known bug that I've since fixed.
** Changed in: ubiquity (Ubuntu) Status: Unconfirmed => Needs Info -- Ubuntu Herd 2 - i386 Desktop CD - Installation Error https://launchpad.net/bugs/80205 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs