Well I might need a url and admin account PM'd to me to determine everything but I would assume it sounds to me like on install you did not correctly enter in the config ( first step ) the proper vb
license number. Also on step 4 you possibly did not set the cookie prefix in vbulletin which is normally bb. These would affect login as well. You could have also not selected the correct dropdown to integrate with vb
and might be integrated with vb2 maybe. Check the first two out first by rerunning install and enter the correct vb
license number and cookie prefix and try logging in again.