No, I don't have an answer to the problem. As any IT support person can tell you, printer problems are notoriously difficult to diagnose, particularly at a distance.
I have used USB printers, and wirelessly connected printers, with OS X for years (both with built in networking and via external print servers), none of which were on the AIRPRINT list. I've also managed Mac using printers shared by Windows Server. All of these work just fine as long as there are OS X drivers for the printer (which covers most printers nowadays).
A company as successful as Apple would never impose the limits that you posit on their flagship OS.
Well, the OP did say what printer it was (it's certainly an OS X supported printer), and what OS version they are using. I've no personal experience with that printer so I can't offer useful advice (which doesn't mean that I am happy to see incorrect advice). An offline printer can be something as simple as a paper jam to a more complicated issue such as a network problem.
I used to find it hard enough to solve some printer problems when I had access to the computer and the printer; without that it's really tough. The best I can suggest is to follow Apple's recommended troubleshooting procedure as detailed here : http://support.apple.com/kb/TS3140?viewlocale=en_US&loc... (It says 10.5 and earlier but these principles hold for any OS version.)