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] => 1927285386606831c9e1053.73293630 ) in lock_release_all() (line 269 of C:\Program Files (x86)\Apache Software Foundation\Apache2.2\htdocs\includes\lock.inc).