Are you trying to connecting to your fax server remotely?
If you are, then you can't. Native win2k/xp server fax service cannot deal with remote clients. Fax Service is not sharable on those platforms.
On the other hand, SBS 2000 can share its faxes.
However, that doesn't mean that you can't send fax remotely. There is nothing to stop you from writing a DCOM or COM+ object to process remote client requests on the server.
HTH