Place ribs in large shallow baking pan, curved side up.
Add 2 cups boiling water. Cover tightly with foil. Bake in preheated 400°oven for 30 minutes. Drain.
Meanwhile, prepare Polynesian Sauce. Place cornstarch in small saucepan. Gradually stir in juice concentrate until smooth.
Note: I think apricot nectar has been removed from the juice aisle because of high sugar. I have found smaller cans in the Mexican food aisle.
Stir in apricot nectar, soy sauce and vinegar. Cook over medium heat, stirring constantly until thickened.
To bake ribs: Place precooked ribs in large shallow baking pan. Brush with sauce. Bake in preheated 300° oven, about 1 hour, basting occasionally with sauce, turning ribs over every 15 minutes.