HELP!

My 4th grade class read a book, but I don't remember what it's called! We watched a movie based on it too. This is what happens in the book:
A mean boy throws a cat down the waterfall, and the other boy went to get it, causing him to fall down the waterfall. And the sister hated the mean boy. Then the mean boy met some old man in the woods and learned to carve and he became nice. He c...arved a toy horse to enter in a contest, but the paralyzed boy's sister smashed it. Then he carves a toy Noah's Ark for the paralyzed boy. Some other stuff happens. And the paralyzed boy's parents learn of a special hospital that can help the boy walk again. They send him there. And I can't remember any more...