Alright, so I have a level 22 assassin on Asia b.net, in Act 2. I got the Horadric staff, put it into the orifice and went in once. Duriel beat the crap out of me, so I left. Now, when I want to kill Duriel, his room isn't opened and I can't get the components of the staff.
What do I do? Is this a bug?
EDIT: Problem fixed, thanks for the help, DoW Fanatic.
When you create a game, is his room not open? Joining a public game where someone hasn't done that quest, will result in it not being open. If you've already completed the quest you won't be able to reacquire the staff parts, like any other quest item. If you're not able to finish the quest, having made the game and experiencing this, then yes it is a bug. Try creating a game with that character and checking first, if you haven't already.