The logs aren't showing anything that indicate a problem, so I'm not sure exactly how to proceed.
I remember some time ago that using "special" characters (è, ö, etc) in behaviors could cause problems with saving, but I think that was resolved. Were you using any of these kinds of characters?
I would also check some of the sample games that came with StencylWorks and see if they behave the same way, or if it just your game.
Beyond that, you may also want to back-up all your games and reinstall SW. I hope we can get this figured out!