I have installed PhotoPost 5 and vBulletin 3 (fresh installation) and done sufficient integration so that PP and VB share the user database and appearance. The problem I'm seeing is that I can't get to the pp5 admin screens. If I try to access adm-index.php, I am asked to log in. I then log in with a set of admin credentials and am presented with the vb3 main page, and if I then try to access adm-index.php again, I am again asked to log in.
Apparently, pp5 doesn't recognize my credentials as an administrator. vb3 recognizes my admin rights, but I can't get pp5 to play along.
Several creative searches through these forums later, I found that PP's cookie prefix was not set to the same prefix used by vb3 and corrected that problem. The behavior I see is still not correct, but has changed.
The first attempt to access adm-index.php prompts me to log in, after which I am taked to the forum. If I then try to access pp's adm-index.php page, I am told that I am "not a valid administrator or moderator!"
FWIW, I am running these systems off of Yahoo! Merchant Services! so I'm not terribly certain of the vintage of the PHP or MySql installations.
More information: After poking around my pp5 database, I see that the usergroups table is empty (0 rows). Instinctively, I think this might be the ultimate source of my problem, but I don't know how to fix it. Any hints would be greatly appreciated.