It is impossible to guess, without knowing what the heck is in the box, like what color and whats tied together. You either have a three way with a pwr. tap or a three way with a double switch leg....very common if lights are seperated by intense framing and long distance, or your at a 4way switch with 4 screws and a grnd. screw?????. at any rate hope this is informing, or re-post with more info and exact nature of problem, and maybe we could be more helpful.