Since my firewall was turned off the emblems was working fine, now if i turned off the firewall players can't see each emblems it's only white.
21 port must be opened, right? ~ and tcp or udp?
Actually, only TCP. People should only to READ the files and sending some request to the server to edit those files and not contacting the FTP server instead.
UDP can be abused and exploited for a complete manipulation of saved emblems and other stuff saved inside the FTP instance.