In the quest the path of the predator that you must compleat to get to lvl 10 where can you find the assassin leader in qeynos harbor. please help i am stuck.
That sounds like the part with the instanced zone. Walk around QH and put your mouse over the doors. One of the (normally closed) doors should glow, and you can click on it and enter the zone.
Been a long time since i played my ranger(over 6 months) but i believe this is the building where if you are coming from the southern part it should be the building on the right just as you pass into the northern open section.