Cannot access my ftp

[siph]

I have cable internet access and I've been using my computer to host an ftp. I've been using it for a few months now and it worked great... until now! I cannot access my FTP from anywhere now. It says that it cannot find my IP (or adresse or whatever it's looking for). My IP doesn't change cause I have cable modem and I can always check what's my IP anyways cause Serv-U (FTP Server) gives it to me anyways. My internet connection works great, my ICQ, even my Napster and some people also download from my Napster also. So what could be so different between Napster and my FTP server? I can exchange files via ICQ, download from the internet and upload to the internet also. JUST CAN'T SEEM TO ACCESS MY FTP. I type in my IP, user name, password, port, like before but the ftp just keeps searching and returns a no find ip after. Worked GREAT before, what could've change it?? I tried to change ports and still nothing. Also, changed FTP server (used WarFTP) but same thing. HELP!!