It looks like to me you overwrote your config files or changed them
You can edit config-int.php with the proper paths and urls and turn on the vb3 enhanced integration. As far as login I am assuming this was working properly before upgrade since the upgrade would not affect this in any way. Make sure as stated if you did upgrade that your correct vbulletin license number is in the photopost config-inc.php file.
That should assist you