Your follow up information points to a problem with some port in the router-portion of your AirPort Base Station not being open to allow the printer to function. I have no idea which port, but since your router is between your modem and your LAN, you should set the ABS to "bridge" mode, which should eliminate the problem anyway. You see, in bridge mode, the ABS simply "bridges" between the wired and wireless networks, without messing with the traffic, so which port is the problem is moot.