More information, please. Most probs with FTP are to do with firewalls. Is your server on a router, or does it have a direct connection to the cable modem?
Many routers have inbuilt firewalls that need to be configured to allow FTP traffic.
So, how does the server connect to the internet? Via a router, or directly?
Cheers
Mick
edit BTW, Welcome to TechIMO!