From EZP Knowledge Base

 Well, first try the following:

• Ensure your firewall is not blocking FTP connections.
• Try FTP'ing directly to the IP address of your site - this info should be in your welcome email you received when you signed up!
• Ensure your FTP program is using the correct path to connect. Your path should be /home/yourusername/public_html/.
• Ensure you are using the correct username and password. Your username and password for FTP is the same as you use for cPanel.
• Try turning on or off Passive mode in your FTP client

If this all fails, submit a support ticket and we will do our best to resolve the problem!