The error Exception: org.ofbiz.order.shoppingcart.CartItemModifyException Message: Could not find a valid price for the product with ID [ENCHILADAS], not adding to cart.
occurring means that you have not set a proper price in the catalog for the product. Furthermore, I have tested adding products to a local instance of 12.04.01, and it works fine. Have you checked whether your products are added correctly to categories? Pierre Smits