Try opening up the OBJ in a modeling program or UVMapper and see if that hip part is in the OBJ or not.  If it is there you should be able to just delete it from you new OBJ and it should be fine.  Either that or try making the hip of you new figure invisible.  To me it looks like a place holder for the hip in the original OBJ file that was hidden later.  Things like that are useful when creating figures using the Old PHI builder method of creating Poser figures

Chris Cox