FTP connection refused

Hi, since i've install a Win2K service pack (with no possibities of unstalling) I can't connect to my FtP server, but i can transfert my files from an other computer who have about the same setup. the specific message from smartftp is : the connection has not been establish because the target computer has refuse it. So how i can resolve my problem without reinstall everything. By the way, now i know i need to wait for installing anything from Uncle Bill !