Uncaught exception thrown in shutdown function.

PDOException: SQLSTATE[40001]: Serialization failure: 1213 Deadlock found when trying to get lock; try restarting transaction: DELETE FROM {semaphore} WHERE (value = :db_condition_placeholder_0) ; Array ( [:db_condition_placeholder_0] => 7896603525edb9ece27afa5.33307446 ) in lock_release_all() (line 269 of /var/www/novagente/includes/lock.inc).