most likely it's because either you don't have hactool.exe or keys.txt in proper path
I was thinking there is a test for missing components?
@Largooo Sure is Developers job. But if we (the Community) can help we should and i think you have these files x times on your HD ;-)
I have hactool... 16 times on mine.
They do a great job in their free time. Building such a big tool is hard work!