Unable to execute retrieveBooks: Got error 28 from storage engine

SELECT books.*, (SELECT publishers_and_imprints.name FROM publishers_and_imprints WHERE publishers_and_imprints.id = books.publisher) AS publisher_name, (SELECT publishers_and_imprints.name FROM publishers_and_imprints WHERE publishers_and_imprints.id = books.imprint) AS imprint_name, TRIM(TRAILING ': ' FROM CONCAT(books.title, ': ', books.subtitle)) AS full_title, TRIM(LEADING 'LE ' FROM TRIM(LEADING 'LA ' FROM TRIM(LEADING 'LES ' FROM TRIM(LEADING 'THE ' FROM TRIM(LEADING 'AN ' FROM TRIM(LEADING 'A ' FROM TRIM(TRAILING ': ' FROM CONCAT(books.title, ': ', books.subtitle)))))))) AS sortable_title, (SELECT GROUP_CONCAT(CONCAT(authors.first_name, ' ', authors.last_name) ORDER BY books_x_authors.position ASC SEPARATOR ', ') FROM books_x_authors LEFT JOIN authors ON books_x_authors.author_id = authors.author_id WHERE books_x_authors.isbn13 = books.isbn13 GROUP BY books_x_authors.isbn13) AS authors FROM books WHERE books.is_drama = '1' AND books.enabled = '1' AND ((books.is_english = 1 AND books.original_language != 'eng') OR (books.is_french = 1 AND books.original_language != 'fra') OR (books.is_italian = 1 AND books.original_language != 'ita') OR (books.is_spanish = 1 AND books.original_language != 'spa')) AND books.synopsis != '' AND (books.is_ebook = '0' OR (books.is_ebook = '1' AND books.parent_isbn = '0')) ORDER BY RAND()