Michael,Have you found an answer to this question?  I am having the same problem but with Cisco IP Phones and Access Points.

This may not be the best solution, but something to try. Thge Dlink is routing as well, or something else is. I would try to plug the dlink into the Internet jack and then plug the Cisco into the Dlink. You may have to use a cross-over cable from ...

Did you have an IP address on your Dlink? Was that IP also your PC's default Gateway?