This is likely an issue with your file explorer, you might have the game's folder or the folder it's in set to read only. I'd bet there's solutions online for this that apply to all RPGMaker games, see if Google tells you anything.
If you're having the issue when you're transferring versions, you can copy the folder called "save" in the "www" folder from the old version to the new one. That should keep all your progress!
