You should check the CD integrity if you doubt that's the problem; I don't think it is, but anyway. Some discs offer (when you boot them) you a possibility to run the integrity check there, to make sure the disc is ok; in some cases the disc "publisher" offers you instructions on how to calculate a checksum of the burned disk and compare it against a known "good" value (usually using md5sum or sha1sum).
Have you tried to use any other distributions; for a start some live-cd distributions, for example Knoppix? Do they give the same error? In case it is "distribution-specific" you could always use another distribution..