I am in the library looking for the secret room. I've used the solvent on the columns, put the rod in the column, tied the rope and grappling hook to the rod, attached the rod to the crocodile. I got the staff from outside and it should be a piece of cake to use the staff on the croc to get him to move...but the game won't let me. Do I have a bug, or is there something I'm missing? Thanks!

Did you tie the rope to the back end of the rod close to the wall?
If it is on the front or long end - the column will not turn and canot be pulled.