It's a children animated movie about a girl and her little/baby sister end up in another world and try to help a boy find this magic jewel or gem. I remember in the end somehow the evil witch has the baby sister and the other boy and girl go undercover into the castle and play the flute to the baby sister. Then the baby sister puts the magic jewel inside a hole in the floor "llike a puzzle" and the evil woman is defeated.

Dragon ball z

Hey!
I was just remembering the same movie! I've been thinking about it lately and It's killing me to know the name. Do you remember the song? Wish upon a dream? Or any of the character's name?