On a side note, I also believe the problem should be as well dealt with at vbulletin, they are the ones to enforce a license, not you, the customer whose vB files have apparently been stolen. You may be suspected to be sharing the files with the "other website owners" but if there's no way to prove that, I believe you should be left alone.
A very valid point. Vbulletin seems to be going down the hill with their customer support as each day passes by.
They won't care. It's a new vB company now.. NOT Jelsoft. It's called vBulletin Solutions now. It is a WHOLE new company. I'd say only 20% of the original team is left. All the old staff resigned and left once Jelsoft was bought.
Contact Howard from piratereports.com He can probably help you out. Usually, he actually posts here too.
with send the same of message at http://www.phpfox.com/piracy/ ?? because been reported at http://www.vbulletin.com/piracy.php
maybe you sold your license here: http://forums.digitalpoint.com/showthread.php?t=1503016 but you're still using it yourself.
it seems to me that one other major option that could be happening is his cpanel/ftp account password being hacked (most likely by a keylogger or some crap like fake admin) Which does so possibly he got keylogged or pass hijacked via a php file like the fake admin one above. Those are my guesses.