Thank‘s for the quick response!
I made a skill tree for actor id 1 with a couple of nodes using the html editor.
I pasted the JSON from the clipboard into text field in the plugin menu as described.
i didn‘t modify the skill trees for the other actors.
I then tried to test run the game. The error will happen immediately. I don‘t even get to the starting screen.
I‘m currently at work so I can‘t try to access the logs until I get home.