In large bowl, combine vanilla frosting, peanut butter and margarine with fork until well blended. Stir in crumbs until well mixed. Form into 1-inch balls; refrigerate 1 hour.

In samll suace pan, melt second can frosting over low heat, stirring occasionally. Using fork or toothpick, dip chilled balls into melted frosting; allow excess to drip off. Place on wire racks over waxed paper; let stand at room temperature until coating is set, about 6 hours.

4 to 4½ dozen candies