Error message/ using steam workshop

Alright so i started modding Game dev tycoon a while ago, and everything was fine until suddenly https://gyazo.com/61b8ef2bdd549b20b01fdef30430e082. I have tried deleting the files and even reinstalling it by removing every file from the folder but this just keeps happening. And mainly when i use fullscreen mode.

Try creating a new savefile.

Restarting the game or creating a save should work.
If not - reinstall it.