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 * FROM {system} WHERE type = 'theme' OR (type = 'module' AND status = 1) ORDER BY weight ASC, name ASC; Array
(
)
 in system_list() (line 165 of /mnt/panlin/includes/module.inc).</p><h2>Additional</h2><p>PDOException: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away: SELECT ff.*
FROM 
{filter_format} ff
WHERE  (status = :db_condition_placeholder_0) 
ORDER BY weight ASC; Array
(
    [:db_condition_placeholder_0] => 1
)
 in filter_formats() (line 434 of /mnt/panlin/modules/filter/filter.module).</p><hr />