Well this script is not written to import 4 images users to vbulletin that much I can tell you.
This little script is written to import 4 images to pro meaning standalone gallery to standalone gallery.
The only way your users would align is if your 4 images was integrated with vbulletin but I do not know there features like I said this is an 8 year old script.
It should work for what its intended to do which is import users categories photos and comments into photopost pro.
where is your pro install at?