Preheat oven to 350 degrees F. Sift rice bran, ground flaxseeds, flour,and baking powder together. Set aside. Cream sugar and butter together. Add eggs and vanilla, coconut . Beat until well blended. Stir in rice bran mixture,then walnuts. Roll dough into small balls. Flatten on cookie sheet. Bake for 12 to 15 minutes. Remove from oven, rest for 1 minute then transfer to cooling rack.