Photopost Pro is not a vbulletin modification in that we do not reside in the
vb admin etc we are a full featured gallery we simply use the
vb header footer style etc. we load vbs replacement vars sure but I assume you would not have defined any replacement variables in
vb just used hard coded links to certain mods you have added therefore you need to use full urls. We rewrite normal
vb links not mods or hacks since our program is designed to work with
vb. we have no knowledge of any other products but
vb. In vbgallery sure since it is a product addon to
vb you can define replacement vars.
this should help
vBulletin Installation/Integration Common Issues and Resolutions.