Brookville area resident  Conrad Eric Barther has been injured in a traffic related mishap, in northern Jefferson County.     And, State Police say that he was transported to Brookville Hospital for treatment.     Barther had been operating an all terrain vehicle on Cemetery Road, about one-half mile off of Route 28, in Warsaw Township.     For unknown reasons, his a-t-v went off of the road and first struck an enbankment.     The vehicle then flpped over, crushing the operator between the a-t-v and the roadway.     Assisting, at the scene, were Warsaw Towmship fire-rescue  and Jefferson County E-M-S ambuance.     This mishap occurred shortly after Five Tuesday afternoon.