I have finished the quest were you bring Enthir the Etching from the stone and Karliah Said she would meet my character at the ragged flagon so i left to the ragged flagon but she has dissapeared from the cellar of the frozen heart and now i cant start the quest The Pursuit Brnyolf Always says "Sorry,lad i have got important things to do we will speak another time" all the time and Karliah never showed up. I really love the Theives Guild Quest and i really want the Nightingale stuff. Can Anyone or Any Bethesda Staff Help me?

You can try the suggestions listed in the bugs section of http://www.uesp.net/wiki/Skyrim:The_Pursuit