Preheat oven to 350° F. In a 13" x 9" pan, melt butter. Sprinkle crumbs over the melted butter. Top with coconut, then the condensed milk. Bake for 25 minutes or until lightly browned. In a small saucepan, melt the chocolate chips and the peanut butter, spread evenly over the hot coconut layer. Cool 30 minutes, and then chill thoroughly.