Paper won't feed from multipurpose tray on 12/640 PS

Hi there: If I try to print anything--paper, labels, whatever--from the multipurpose tray the paper jam light comes on instantly, even though the paper never budges a millimeter from the tray...it doesn't seem to get touched by any mechanism at all. Plus there's a brief (no more than a second) but quite noticeable sort of groaning sound that emerges. Apparently I need to do something to a roller, from what I'm finding out, but I don't see any details on how to disassemble anything to get at whatever roller might be the issue. Is this something that the $30 kit from the fix your own printer folks would address, even though they say there's no kit for this printer (+It appears there are no printer repair kits available for your printer (apple 12/640).+)? If someone could please point me in the right direction I'd be very grateful. Thanks in advance! Bill