Unable to execute retrieveAuthors: Got error 28 from storage engine

SELECT books_x_authors.*, authors.*, TRIM(CONCAT(authors.first_name, ' ', authors.last_name)) as full_name FROM books_x_authors LEFT JOIN authors ON books_x_authors.author_id = authors.author_id WHERE 1=1 AND books_x_authors.isbn13 = '9781550718072' GROUP BY books_x_authors.author_id ORDER BY books_x_authors.position