Windows Terminal Services Licensing

I have recently upgraded two of the servers in my office to Windows 2003 servers. One of these servers is the PDC and the other is the BDC. I also have a Windows 2000 server that has not yet been upgraded. The Windows 2000 server has Terminal Services installed and had 25 terminal service licenses installed. Since the upgrade, I can’t connect to a licensing server for the Terminal services licenses and the Terminal server can’t allow new connections. Can someone tell me how to remedy this situation? Where did the licenses go?