Hrm. Thats a new one 
… What OS?
Also, make sure you are using V1.0.2 - the first version wont work on Win10.
I think this is a bug. I’ll do a couple of tests on some other machines I have here. Gimme 10 mins.
Oh. Also, which Blender? > 2.8?
Ok. Latest seems ok on Win10. Did you install via the addon Install method?
The dir variable should be getting set, there are a couple of ways it may not - try saving your scene as a blend scene first.