In a small skillet heat margarine or butter over medium heat until melted. Add chopped apples and onion; cook over medium heat about 5 minutes or until tender. Remove from heat. Stir in wine or apple juice, brown sugar, and caraway seed. Drain sauerkraut; rinse with cold water and drain well. Combine sauerkraut and apple mixture, mixing lightly. Tear off a 36x18-inch piece of heavy foil. Fold in half to make a double thickness that measures 18x18 inches. Place sauerkraut mixture in center of foil. Bring up edges slightly to hold juices. Bring up two opposite edges of foil and seal with double fold. Then fold remaining ends to completely enclose sauerkraut mixture, leaving space for steam to build.
Arrange preheated coals around a drip pan in a covered grill. Test for medium heat above pan. Place ribs and foil packet on grill over drip pan. Cover and grill for 30 minutes. Brush ribs with some of the apple butter. Cover and grill for 30 to 35 minutes more or until ribs are tender and no pink remains, brushing ribs occasionally with apple butter. Partially open sauerkraut packet to make a 5-inch opening for the last 15 minutes of grilling. Serve ribs with sauerkraut mixture. Garnish with apple slices, if desired. Makes 6 servings.