Thank you for acquiring the game. Unfortunately, I'm not familiar with the error you mentioned. I conducted tests to review it, and saving works correctly. It's difficult to pinpoint what might be causing the issue. Are you experiencing this in the Windows or macOS version? If it's on Windows, you could try deleting the "save" folder to allow RPG Maker to create a new one. Does the autosave function work? Can you load a game from the autosave?