I am trying to complete the quest for the thieves guild in the HUB. I am supposed to find the necklace at Hightower's place. Well I am at his place and found the locked strongbox containing the necklace. Problem is that it's locked and my lock picks do nothing. It just says, "That does nothing" when I try and lock pick it. My lock pick skill is at 100%, what am I missing?

Blah I'm a fool. If anyone else has this problem it was because I was using my lock picks on the box. Had to use my skill instead. Durrrr