Uncaught exception thrown in shutdown function.

PDOException: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away: DELETE FROM {semaphore} WHERE (value = :db_condition_placeholder_0) ; Array ( [:db_condition_placeholder_0] => 206488115266df89437f8957.62642876 ) in lock_release_all() (line 269 of /home/admin/web/infosheet.org/public_html/mm/includes/lock.inc).