OK, I see what's going on - for now, you can simply delete the settings file in that folder (or set the font filepath directly, as you mentioned), and MasterPlan should load. The issue is, as you pointed out, that the path does exist, but it simply goes to a directory rather than a font file. That was a possibility that I hadn't considered - the fix for this will be in the next build. Sorry about that, and thank you for your patience!