Comment 7 for bug 376300

May 14 01:48:24 kernel: [ 1512.636906] sr 1:0:0:0: [sr0] Unhandled sense code
May 14 01:48:24 kernel: [ 1512.636918] sr 1:0:0:0: [sr0] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
May 14 01:48:24 kernel: [ 1512.636928] sr 1:0:0:0: [sr0] Sense Key : Medium Error [current]
May 14 01:48:24 kernel: [ 1512.636940] sr 1:0:0:0: [sr0] Add. Sense: No seek complete
May 14 01:48:24 kernel: [ 1512.636952] end_request: I/O error, dev sr0, sector 994540

Either your CD drive is busted, or the CD is dirty (try cleaning it?), or the kernel is handling it wrong; in any event this isn't an installer bug. Unfortunately the integrity check is not 100% reliable at catching this kind of problem.