In a small bowl, combine cake mix and water; beat on low speed for 30 seconds. Beat on medium for 1 minute. Pour into an ungreased 11x7-in. baking pan. Bake at 350° for 20-25 minutes or until golden brown and entire top appears dry. Cool completely, about 40 minutes.
In a small bowl, whisk milk and pudding mix. In a small bowl, beat cream cheese until smooth; beat in pudding mixture until blended. Run a knife around sides of pan. Remove cake and cut horizontally into two layers. Place bottom layer on a serving plate; spread with half of pudding mixture. Top with remaining cake layer and pudding mixture.
In a small bowl, combine the raspberries, blackberries and sugar. Serve with cake. Refrigerate leftovers. Yield: 8 servings.