I have patched the game with the latest official patch and the unofficial patch. The quest which involves retrieving the ceremonial dagger for the mayor of Blackroot seems to be broken. I can get the quest and retrieve the dagger ok, in my case by pick-pocketing the poison from the alchemist and giving it to the elf-thief who gives me the dagger. But when I return to the mayor, no conversation option comes up to finish the quest. He just answers with one liners. I definitely have the dagger in my inventory. Any ideas what's going wrong and what I can do about it?