Yeah, that is definetely occurring because there are no cursors properly configured. It's not even that there is no image set, is that there is no cursor pattern configured (which has the parameter to load the image within it).
I've added an exception handling on version 1.0.2, which I'm uploading right now. It will prevent the game from crashing if it is run with the plugin active without proper configurations. Even though the game will continue playing, if it happens you will still get error messages in the console to let you know something is not right, and you may not see any cursors at all on the screen.