Combine first 5 ingredients in a large bowl, and stir well; make a well in center of mixture. Combine pumpkin and next 3 ingredients in a bowl; add to dry ingredients. Stir just until dry ingredients are moistened. Fold in dates and walnuts. Spoon batter into an 8 1/2 x 4 1/2-inch loaf pan coated with cooking spray. Bake at 350° for 60 minutes or until a wooden pick inserted in center comes out clean. Let cool 10 minutes in pan on a wire rack; remove from pan, and let cool completely on wire rack.