Heat oil in medium saucepan. Add celery, onion, and green pepper and saute for 2 minutes. Add corn, potatoes, water, salt, pepper, and paprika. Bring to a boil; reduce heat to medium; and cook, covered, about 10 minutes or until potatoes are tender. Place 1/2 cup milk in a jar with tight fitting lid. Add flour and shake vigorously. Add gradually to cooked vegetables and add remaining milk. Cook, stirring constantly, until mixture comes to a boil and thickens. Serve garnished with chopped fresh parsley.