I suppose this is really more of an FYI, than a general inquiry. However, I didn't see it listed anywhere (in SmileBASIC documentation or on this site), so I'm leaving this here.
It appears that the SAVE function limits the filename string to 14 characters. If you use more than that, it will error, with a rather unhelpful message. This cropped up in one of my applications where I allow the user to specify the name of saved files.