It works on a default installation (I've just tested it on mine) - we're going to need a support ticket so we can have a look at your setup.
http://www.vbulletin.com/go/techsupport
We'll need:
AdminCP login credentials
FTP server URL
FTP server login credentials
http://www.vbulletin.com/go/techsupport
We'll need:
AdminCP login credentials
FTP server URL
FTP server login credentials
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