Grease and flour bottom and sides of 9x5-inch pan.
In large mixing bowl, combine 1 1/2 cups firmly packed dry frosting mix, flour, baking powder, soda, salt, eggs, oil and prune filling.
Stir until well blended.
Fold in walnuts and graham cracker crumbs.
Pour into pan.
Bake at 350° for 60 to 70 minutes until top springs back when lightly touched in center.
Remove from pan.
While warm, frost with Glaze.