FTP over Microsoft Proxy Server

Can anyone help?

I have implemented Microsoft Proxy Server in our offices here. My problem is that while I can open ports up for the internet traffic and everything is fine, I have been unable to connect to any FTP sites thru IE or use an FTP client from my workstation (server works fine) it brings the line up – attempts connection and then sits there and times out.

The Server is NT4 SP6a and Proxy 2 has had SP1 applied.

Can anyone suggest a possible cause for this?

Pleeeeeease….Nick