Like any plugin, you need to tinker with things until you get the hang of it.
But this plugin works out of the box on any theme in WP 3.5.1. When you set it up, make sure you create a category first. Then you create a forum. For instance, I created a category, "HLN Sociopath Anchors", and my first forum was "Nancy Grace".
Then I was able to post threads in the Nancy Grace forum.
My next category will be "Jodi Arias" and I'll have a forum for Jodi Arias, Travis Alexander, Rock Star Juan Martinez, and so on.
So great plugin, works out of the box, and just work on setting things up. Nice work!