Jezus Christ! my current quest is "The Ultimate Heis" of the thieves guild i entered in the palace and i found the monks! I ACIDDENTLY Pushed the X (Ps3 version) and talk to one of them in left the palace and now i can go back to the palace again! Becuase the enter in the Arrow of Exentrication part doesnt open because is necessary a KEY!!! HOW CAN I COMPLETE THE QUEST WITHOUT THE ELDER SCROLL?? :cryvaultboy:

Previous save?

unfortunately there is nothing you can do, unless you can go back to a previous save like Troyatz mentioned. other than that i'm afraid its impossible.