Internet Connection Sharing with Win 200

Hi,
I am running win2000 server on a 866 Micron P3 using 384 mb ram. I recieve
an ISP connection on my server through a digital provider. I have shared
that connection through a 2nd NIC adapter on the server.
The connection works fine on all theclient PC’s except for the fact that I
cannot download on the the client connections. I do not have a firewall that I know of and have checked security settings on all the browsers.
Im hoping that one of you more skilled in this matter can help me.
Thank You for your assistance,
tavarish