I had the same problem. I routinely boot various Dell/Compaq/HP machines, using one CD-R (a TDK) I burned a few weeks ago. I just had another system with this problem, kept retrying over and over, as eventually that seems to work.

I just tried using 'nodma' and it worked miraculously, first try.

the optical drive is a Hitachi/LG GWA-4166B.

Also, to above post: Live CDs lock the optical drive so you can't take the CD out. Just restart and go into the BIOS or Boot Menu and you can open and close the drive.

Edit: I just tried it again to be sure. 'nodma' has fixed my problem this time.