1) Don't post the same thing in multiple forums. It is considered spamming the forums. Imagine how cluttered and repetitive these forums would become if everyone who wanted an answer did that. Your other duplicate post has been removed.

2) You don't give enough information about what is happening for anyone to really know the answer, but I would guess you didn't make the CD properly this time even though you imply you made a good CD before. There are a number of things that can go wrong. And you mention using a mirror rather than using BitTorrent, so it's not unlikely that you simply got a bad download and never even bothered to test the md5 checksum. See answer #1 for a more detailed list of issues and approaches to getting the disc right.