Hello, thank you very much for commenting. From what you tell me you can play the game perfectly well, can't you? But when you enter the "extras" section and go back to the main menu, the game crashes with this message, doesn't it? Is that right?
I'm very happy to hear about this error so that I can try to see where the bug might be. Unfortunately, as you say, Visual Novel Maker is not a great game engine and is quite neglected; so much so that there are features (such as autosave) that don't work. So it's frustrating when the game has bugs that you can't fix; I hope this is not the case.
Best regards and thanks again.