Then you've edited some scripts wrong or you're not connecting the maps correctly, make sure when you "connect the maps" you link the outlines, not the tiles, the outline should become a thick black line as opposed to a slim black line when you first add a map! If you over lap or not close enough strange things happen, like your player disappearing or something!
A screenshot of your connections in the editor may help, along with a screenshot of you in-game.