It COULD be caused by bad data on the cd. Did you check the md5checksum on the iso after downloading? It happened me too often that I had a bad image downloaded (and sometimes I just found out after burning and (trying to) install).
Maybe you can use bittorrent, it checks its data. a downloaded bittorrent file is always ok, thats why I use it for big files... (on the anouncement-forumpage you can find a bittorrent-link)
