I'm still trying to resolve this issue, but am finding the plug-in works in VB 4.08 in a forum I created PRIOR to upgrading to 4.08. If I try to create a new forum, update an existing forum or make a new forum based from the one that is working (now that I am on 4.08), the plug-in permissions do not prevent users from accessing the forum if they do not have the minimum post count.
If somebody reading this post is using this plugin and it is working correctly on 4.08, can you try to create a new forum and test to see if anything created after you have upgraded to 4.08 doesn't work. Just trying to see if others are having the same problem based on when they created the forum.