The Tip.it guide for this quest is incorrect. It says you need to try and pickpocket father Urhney and then distract him by making some fires under his windows. But you won't get the option to say 'fire! FIRE!', you must talk to Chief Thief Robin first, and when he tells you to make a fire under the window you will get the chat option. It is really anoying to make a fire, and find out it doesn't work and then go back to Lumby castle and back to the shed to make a fire again.