fax through sever 2003

I have a client who wants to be able to fax from any of the computers
on the network using outlook 2003. the fax modem is installed on their
server which is SBS 2003. This was previously set up on a different
server for them, but that server is no longer functional (it was also
SBS 2003). because this is an inherited network i am not certain how it
was setup. now everytime they try and fax they get a messege in outlook
stating that it was undeliverable. If this question has been answered
before; please let me know where. otherwise please help