Crashes if screen not selected

I recently installed this and I didnt set the screen for one of the extra slides, this ended up crashing the plugin, I cannot delete the extra slide or anything else with the error. Please let me know how to fix this. I tried uninstalling the plugin, but it remembered the screen and extra slides. I think this might be good for an upcoming project but I can’t test it any more.

Thanks for any help you can offer.