I have experienced this same issue, and it was a known issue with "Alternate" CDs at the time. Have you tested any of the latest daily releases to see if it is working yet? I just tried a daily the other day and had issues in VMware with it, haven't had a chance to test it on a separate desktop just yet.
** Changed in: ubiquity (Ubuntu) Importance: Undecided => Low Status: Unconfirmed => Confirmed -- Feisty fails to dectect CDROM https://launchpad.net/bugs/84895 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs