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 dft.type, dft.title, dft.locked FROM {date_format_type} dft ORDER BY dft.title; Array
(
)
 in _system_date_format_types_build() (line 3771 of /mnt/panlin/modules/system/system.module).</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 />