If you connect successfully to your FTP account, please try the following troubleshooting steps:
1. Change the FTP mode to PORT in your FTP program.
2. Disable or reconfigure the Windows firewall. (Please see support.microsoft.com/default.aspx?kbid=842242 for more information)
There are alternate firewall programs such as Zone Alarm which do not seem to cause this type of problem. If you are still unable to transfer files, please contact your ISP to determine if a network error is causing this issue.