It's so long ago since I set mine up that I'm not even sure where to begin. From memory, there are three things you need to have configured:
- The Print Server's IP address.
- Recognition by the Print Server of the Printer attached to it.
- The creation of the Virtual Printer Port in each PC that prints via the server.
I have actually given mine a fixed IP address of 192.168.3.30 (my Router is 192.168.3.1), so that I know what its address is. If allocated dynamically by DHCP, its address is unknown which makes it inaccessible. By typing 192.168.3.30 into my browser, I can open its configuration pages directly:

Not sure if that helps, but make sure (a) each PC does have the Virtual Printer Port, by running the CD if necessary, and (b) that the correct Printer is set in the server's configuration.
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Mike