“Who do you hoodoo?” would have been a fitting tagline for The Skeleton Key, a blundering New Orleans-set thriller under the spell of archaic stereotypes about Southern Bayou blacks. Disgusted by the medical establishment’s impersonal treatment of the elderly, Caroline (Kate Hudson, with straight hair impervious to humidity frizz) takes a job working as an in-home hospice caregiver for the stroke-afflicted husband (John Hurt) of a crotchety Southern dame (the hammy Gena Rowlands). Caroline is disturbed by the house’s lack of wall mirrors and the secret attic room filled with black magic knickknacks that belonged to the prior owners’ African-American servants, a duo strung up for practicing un-Christian enchantments on their employers’ white-as-snow children. Until the rather effective and creepy Twilight Zone-ish denouement, Iain Softley’s sub-Angel Heart gothic mystery proves unpleasantly infatuated with the image of Southern blacks as wholly superstitious simpletons or nefarious witch doctors (a fact unaltered by its supposedly subversive ending). When compared to such hoary, ugly characterizations, a few satanic symbols and dolls with their eyes and mouths sewn shut don’t seem half as frightening.