since you haven't successfully logged in before, it sounds like your download didn't go so well (or, possibly the cd burn).
I would check the md5 of the download. if it doesn't match, re-download the image. if it does (and, even if it doesn't i suppose ) re-burn to disc using the slowest speeds possible and perhaps with some sort of media check enabled to ensure that all is well. then try again.
good luck with that.