Many possibilities as to what's gone wrong -- perhaps the site is dynamic, and presents different pages depending on the useragent string. (In which case, check out the --user-agent option).
Or perhaps it's doing a redirect (-L option to follow).
Or perhaps it requires cookies to be set -- check your cookies from that site in Safari, and if some are set, try downloading them with --cookie-jar <filename> first, then reading & transmitting them with -b <filename> on a second connection.