What's in a title? In the world of direct-to-video movies, it's usually another title. Last fall Academy Entertainment released the erotic thriller Animal Instincts nearly simultaneously with Basic Instinct. Similarly, its latest salacious offering, Body of Influence, suspiciously resembles Madonna's recent soft-porn courtroom drama, Body of Evidence (scheduled for June release). Academy's tape was originally called Indecent Advances, but the company says the name change had nothing to do with the more-famous flick. Body of Influence ''was a better title,'' says vice president of marketing M.J. Peckos. But what does it mean? ''There's a lot of influence used back and forth between psychiatrist and patient,'' Peckos says. Sounds as if it should have been called Body of Nonsense.