One thing in the walkthrough that is different is the Patronus charm. It says make a triangle over the demontor after tapping the blue cloud circle . . . well that works just as well as the white circle. Just make sure you end up on its face.
I have not been around here much due to being stuck with the two preceptors in the Pettigrew level of game III.
The Pettigrew level is just a matter of timing....when one walks away, follow him, then he'll turn a corner and you can keep going (you need to go right eventually), then when you go back, do the same thing...just time is so that you're moving with them, not against them.