The abbreviation E & O.E. on an invoice stands for "Errors and Omissions Excepted". It indicates that the seller is not liable for any errors or omissions on the invoice and that the document is not intended to be a legally binding contract. It is a way for the seller to protect themselves against any inadvertent mistakes or oversights that may occur during the preparation of the invoice. Therefore, the correct answer is that E & O.E. seeks to protect the seller against any error on the document.