Interesting. I just discovered that it works fine if I launch from command line ./zoopertracker.app/Contents/MacOS/zoopertracker but not if I load the app through Finder.
I guess this is Finder not setting the current directory when launching an app. That would explain the difference. I’ve never built a Mac app bundle before so not sure how that works.
Oh, that's interesting to know. I'll investigate what the difference is when running through Finder instead of command line. Thank you for testing and reporting this. At least for now you can run it via command line, and I'll hopefully have it fixed in next update :)