This is what the Walkthrough at gamebanshee says about the door.
11 - Locked Door & Secret
Toorum's note, found at (10), will reveal the general method on opening this locked door. The correct sequence of events to perform is: pull lever down, press right-hand button, pull lever up, press left-hand button. You'll be attacked by three Herders who have apparently grown from Toorum's leftover Herder Caps - kill them and step inside to claim your prize, a Herder Cap and the Conjurer's Hat.
But I dont get this working.
I have tryed what they say, Lever Down turned left goto that button push the back to Lever Up and push the other button, No Luck. So I tryed the other way round with the Buttons.
Still no good?
Anyone help with this?