Frozen Yogurt With Rum-Raisin Sauce

Combine first 3 ingredients in a small saucepan over medium heat; cook 3 minutes or until margarine melts, stirring occasionally. Combine flour and milk in a small bowl; stir with a whisk. Add milk mixture and raisins to pan, and stir well. Cook 5 minutes or until thick, stirring constantly. Remove from heat; stir in rum flavoring. Serve over frozen yogurt.