Additional uncaught exception thrown while handling exception.

<h1>Additional uncaught exception thrown while handling exception.</h1><h2>Original</h2><p>PDOException: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away: SELECT alias FROM {url_alias} WHERE source = :source AND language IN (:language, :language_none) ORDER BY language ASC, pid DESC; Array
(
    [:source] =&amp;gt; node/751/revisions/212198/view
    [:language] =&amp;gt; en
    [:language_none] =&amp;gt; und
)
 in drupal_lookup_path() (line 150 of /var/www/2.0/includes/path.inc).</p><h2>Additional</h2><p>PDOException: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away: SELECT expire, value FROM {semaphore} WHERE name = :name; Array
(
    [:name] =&amp;gt; rules_get_cacherules_event_whitelist
)
 in lock_may_be_available() (line 167 of /var/www/2.0/includes/lock.inc).</p><hr /><h1>Uncaught exception thrown in shutdown function.</h1><p>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] =&amp;gt; 12280056986a7af20b3e0b21.16835767
)
 in lock_release_all() (line 269 of /var/www/2.0/includes/lock.inc).</p><hr />