Sift together flour, baking powder and salt; set aside. Melt butter. Add sugar and beat until well mixed. Let cool slightly. Add eggs one at a time, beating well after each addition. Stir in dry ingredients, followed by vanilla. STir in nuts and carob chips. Turn into lightly oiled 9 x 13-inch pan. Bake at 350 degrees for 25 minutes. Let cool. Cut into bars.