Spread cherry pie filling over the bottom of a 9 x 13 pan. In a large bowl stir flour with sugar, cocoa, soda, and salt. In another bowl, combine the water, oil, vinegar and vanilla. Add liquid to dry mix all at once. Stir just to moisten. Pour batter evenly in the pan over the cherry filling. Bake in a preheated 180ºC oven for 30-35 minutes. Cool 10 minutes in pan; invert onto plate and cool. ----