I dont think that would make any difference. It's its own voodoo weapon and the level of your doll shouldnt matter, just like the level of your cutlass didnt matter when tryint to do quests for the dagger (that I know of).
Unfortunately, I think the quest is just bugged. I've personally never seen anybody with a voo doo staff. I've heard that somebody had one, but have to wonder if that was a developer, too, because I dont know anybody over level 30 yet that has one.
Happy plundering anyway!
