Good thought, James. But, I am guessing with a domain, he is using a static IP. At least I hope.
@ihstech First, can you put your first name in an auto-signature. Hard to write ihstech.
Yes, you are correct, the XML file is on the main computer (server) and has the port and the path to the database. Wouldn't hurt to look in it. Also, try the IP. As Indy says or as my IT person says, think DNS, DNS, DNS, then everything else. The clients will have to resolve the server name to the IP but not if it is the IP.