Reinstall the patch again and see if the problem continues. If it does reinstall the game and apply the patch.
Does the error occur when trying to start Divinity 2 from the desktop? (if no, answer the last three).
Does the error occur when trying to load previously saved game?
Does the error occur when trying to save a game?
Does the error occur when creating a new game?
Type what the error code says (as best you can with an English keyboard).