1. In a large bowl, dissolve gelatin in boiling water. Stir in sherbet until melted. Pour into an 8-cup ring mold coated with cooking spray. Chill overnight or until firm.
2. In another large bowl, combine the pineapple, oranges, coconut, marshmallows and sour cream. Cover and chill. To serve, unmold gelatin onto a serving plate. Spoon fruit mixture into center of ring. Yield: 12-16 servings.