Help, got FTP problem

hi, i have some problem when i try to set up a ftp server on a different port, the story goes like this. me and my cousin both has a FTP server computer that runs U-serv. and it runs fine with my ftp server. then my cousin took over port 21 from me for his server and now i have to use a different port for my server. as i went thought some tut. and get the server set up on a different port, it's not working right. i can login but i can't get a dic list from my server, error is trashed info received. then i tried the PASV mode and it gave me error said control connection closed. we have 1 wireless-n router and 2 wireless-G (wireless G work as access point) and i try to use port 6200 and i did all the port forwarding in the router, so please help to get it work, thanks