Preheat oven to 350 degrees. Spray a 9” pie plate with nonstick cooking spray. In a bowl, combine crumbs and margarine with a fork. Press crumbs into the bottom and up the sides of the pie plate. Bake for 5 minutes. Cool.
Next, arrange bananas over crust; set aside. In a small saucepan sprinkle gelatin over cold water and let stand for 2 minutes. Add sugar, then cook over medium-high heat until mixure boils and the gelatin and sugar dissolve.
Remove gelatin mixture from heat. Stir in the yogurt and vanilla. Pour into the pie plate, over the bananas. Cover with plastic wrap, and refrigerate until chilled.