Did you check the md5 sums when you downloaded the iso files. You may have gotten a bad download. It also could have messed up during the burning process. I have always had trouble burning iso's for some reason. I think it was the configuration of my drives though since I had two cdrom drives. It also could have been a bad disc. Check for scratches on the disc. Also, for redhat did you download the files and burn them with the same process, or did you buy the discs or have a friend do it? If you did the same with redhat, I would say that it's not your software or burner, but just a bad download, corrupt file, or a messup in the burning process. When you're burning the iso's, don't do anything else in the background, just set it to burn and come back in about 8 minutes.
Hope I helped