PREHEAT oven to 375°F. Mix water and flour with wire whisk in large saucepan. Cook on medium heat, stirring constantly, until mixture comes to full boil. Add dry gelatin mix, 2 Tbsp. of the sugar and fruit; mix well.
POUR into 8-inch square baking dish. Mix baking mix, remaining 2 Tbsp. sugar, cereal and milk in large bowl. Drop 8 heaping spoonfuls onto hot fruit mixture.
BAKE 30 min. or until topping is golden brown. Let cool 20 min. Serve warm with whipped topping.