So this plugin seemed a bit abandoned and I’m in the process of taking it over / branching it. However for those of you who need a quick fix (I’m going to make this plugin all around better by completely redoing it but this is a quick fix). I’ve uploaded a zip of the plugin working for Shopp 1.2.x (it was crashing on start before).
Download Fix Here (tested with Shopp 1.2.1).
If you have any problems or are looking for a developer to help you with a Shopp implementation drop me a line!.