For whatever reason, John, one of the users has had better luck using the IP address of the server rather than the name of the server.
I have seen this in facilities that we get brought-in (remotely), and that comes down to a DNS resolution problem.
Try pinging by name, and see what resolution you get.
Another thing to do is open up the XML file itself and see what is in there - assuming a static IP for the server, you can try replacing the name with the static IP.
