I've played this game 3 times and here's what
always worked for me.
1. Make sure the red mountain is at the top and
the turtles nose is facing it.
2. Your standing at the tail end of the turtle.
3. Take two steps to your left toward the window.
4. Go left one step, your now in the corner.
5. Turn around and take one step forward.
6. Turn right and walk all the way around the
7. When you get to the other corner (on the right side of the window)
turn right and step forward once. Now you should be able to click on the dragon's head on the wall and the door will open.