To see the true error you would need to click the console tab. I might not be able to solve it, but it can sometimes give a clue about the problem.
This was made in an older version of the engine. I'll have to look into it and try to update to the newer one and do a little more work. I stopped because it lags for me, but there was an improvement so it might work better now.
If you want this to work you can always reinstall Paper Maker and choose version 2.0.7. But it's pretty short and maybe not worth it yet.
Here are all the errors on what look like the "Browser".