This warning appears to inform you that the New ASIN/ISBN creation functionality was disregarded because the Search Settings are enabled and the UPC/EAN value is provided.
If your product is new and does not exist in Amazon Catalog yet, you can list it under a new ASIN and the Search Settings should be disabled.
If this Product is presented in the Amazon Catalog, you should adjust Search Settings to find existing Amazon ASIN and list your product under the existing ASIN.