I'm completing the Knights of the Nine quests on Elder Scrolls IV Oblivion. I've arrived at Garlas Malatar and seem to be stuck near the entrance with no sign of what to do next. Just beyond the first room there are 3 gates which need to be opened to proceed onward. When I try to activate the push block in the first room nothing happens.

I've looked this up in the walk-through on wikipedia and it says that the block should open all 3 doors but no matter how many times I activate it the doors don't open. Anyone know how to get the doors to open?