Is the file sitting in the queue, or does it pass through and just not print? I am guessing that you set the printer to a jet-direct and is operating over port 9100. Can you telnet to the printer, and if so, do you have the cups-lpr system in place? Also, is this a domain controlled printer, and are they using printer queue authentication through the domain?
Mixed environments can be fun...
Let me know what you get back, and we can continue from there.