The tree puzzle solver is currently Bugged! I will work on a fix as quickly as my schedule allows for it.
Before I come up with a fix, you can try:
- Stand in an area with very little brown color in the area (Falador, Varrock, etc.)
- Have the empty tile of the puzzle be on the top right of the puzzle. A user has feedback that this works for him as a temporary workaround.
I'm really sorry for the inconvenience!