Here are a couple of basics to consider (if you haven't already):
1. Are you able to boot to the LiveCD (if not probably a bad download-burn)?
2. Can't remember as it's been a while since I booted the LiveCD, if the Live has a Check CD option run it if you haven't already.
3. When you burned the iso image, did you reconcile the md5 checksum?
4. As a last non-technical resort, I'd recommend downloading it again (possibly choosing another source). Reconcile the md5 before burning the iso. Burn the iso image to the CD at the slowest speed you can.
Linux'd since 2005 Linux ID 422356 Ubuntu ID 15015