On step 4 of install you have not input the correct mysql table prefix for vbulletin. Your config file in vbulletin should have all the forum correct mysql info
On the last step of install you fill out the server paths and urls of the forum and photopost and turn on the 3 vb3/vb4 switches to load the vb
header footer and style
My suggestion is thus rerun the install and run through it again answering everything correctly and you should be okay.