Preheat oven to 350 degrees F (175 degrees C). Melt and spread 1/2 cup margarine in the bottom of a 9x13 inch pan. Sprinkle coconut and pecans evenly over the bottom of pan; set aside.
Prepare cake mix as directed on package. Pour batter over coconut and pecans in pan. In a saucepan over low heat, melt cream cheese and 1/2 cup margarine. Stir in confectioners' sugar until mixture is smooth. Spoon cream cheese mixture randomly over top of cake batter.
Pour batter into prepared pan. Bake in the preheated oven for 35 to 40 minutes, or until a toothpick inserted into the center of the cake comes out clean. Allow to cool and serve from the pan.