well you would clear your usergroups table in the photopost database before reinstall so your phpbb3 and the usergroups can align correct
as far as images not showing right it looks to me like your server paths are not correct for your data and uploads directories so recheck those in global and storage options example this image does not exist on your server why?
http://ascrappinfriendsy.com/photopo.../IMG_3051a.jpg