Sounds like a failing drive. Will it boot other bootable CD's?
Edit: Oh, the drive reads other disks fine but not the recovery disk? Just because another computer reads a disk does not make the disk a "good" disk. Scratches, even small ones, and dirt can cause some drives to fail reading them.
Make sure the disk is clean. If it has scratches try cleaning it with furniture polish that has wax in it. The oil and wax in furniture polish help mask the scratches so the laser can read them better.