seems like a hardware issue.
Did you run the md5sum or sha1sum on the downloaded iso
and also check the media during the install?
How old is you CD? Clean it. Does it have an 80 wire cable?
Did you burn are about 12x or very fast?
Is the media a 703 CD or a 700? Use a 703.
Look for scratches on the cd's and in the cd-rom tray.
Look for cheese and hair.