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] => 8728230956605b36a1ebdb8.29252899 ) in lock_release_all() (line 269 of /home/novagente/public_html/includes/lock.inc).