well that leads to a cookie issue difference between the two products
If you have a cookie on your computer when logging to photopost yet you logged into the forum with test you would see this kind of issue.
Check your cookie settings between both products
I suggest
VB set to
cookie path /
cookie domain .domain.com
Photopost set to
cookie path /
cookie domain .domain.com
cookie prefix bb
vb license --- this must be entered in the photopost config for cookies to mesh