Another thing:
I tried to restart the game (from Itch), but it then asked me to re-install the game, so I did. But now I can't start the game anymore, I get this error:
And when I click OK it mentions "map/field2.tmx" and "5".
I already tried re-installing the game several times more, also trying to install it in a new folder, but nothing helps.
What should I do? :o