1. the german spelling would be "Rumpelstilzchen".
2. they are fairy tales, and, as such, not meant to make sense. and they mostly do not, because, if they would, the whole construct of moral teachings that is being built by problems and situations removed from the reality of the children would not work. seriously, while we're at it, why didn't snow white's mother just stab her? why didn't haensel+gretel's parents simply make sure they would not come back? because the story just wouldn't work that way.