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