Sharing a modem on Win 2k Server

I have 4 machines connected to an 8 port d-link switch which is in turn connected to a win 2000 server. i have a modem installed in the server (hmmm) and i want to be able to use this modem as a connection to the internet from my four workstations. i have installed active directory and the network is tip-top.; however when i set up ICS and set up the IC wizard on the workstations to connect through my modem it doesn't want to work. in IE on a workstation if i enter a web address it konks out and doesn't work. if i enter an ip address outside of my network it dials the modem but can't get a connection. according to Microsoft Knowledge base i can't share a modem connection across a LAN using win 2k server. i don't believe that. I think it has something to do with my DNS routing settings and possibly NAT, but i just cannot get it to work. Active directory is set up correct, as far as i am aware.

any help would lbe appreciated.