caught exception when trying to configure a nicemenu or a superfish

Hi everybody

I install Pixture reloaded. Everything is ok, but when I put a nicemenu or a superfish on the navbar, and then i try to configure it (by different ways), i am redirected to this page :http://localhost/drupal/fr/admin/structure/block/manage/nice_menus/1/con...
and on the page i have this:

Additional uncaught exception thrown while handling exception.

Original

PDOException: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away: SELECT s.lid, t.translation, s.version FROM {locales_source} s LEFT JOIN {locales_target} t ON s.lid = t.lid AND t.language = :language WHERE s.source = :source AND s.context = :context AND s.textgroup = 'default'; Array ( [:language] => fr [:source] => Configure how content input by users is filtered, including allowed HTML tags. Also allows enabling of module-provided filters. [:context] => ) in locale() (line 720 of C:\xampp\htdocs\drupal\modules\locale\locale.module).

Additional

PDOException: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away: SELECT s.lid, t.translation, s.version FROM {locales_source} s LEFT JOIN {locales_target} t ON s.lid = t.lid AND t.language = :language WHERE s.source = :source AND s.context = :context AND s.textgroup = 'default'; Array ( [:language] => fr [:source] => The website encountered an unexpected error. Please try again later. [:context] => ) in locale() (line 720 of C:\xampp\htdocs\drupal\modules\locale\locale.module).
Uncaught exception thrown in session handler.

PDOException: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away in _drupal_session_write() (line 209 of C:\xampp\htdocs\drupal\includes\session.inc).

I am not a developper. Is there anyone who knows how to solve this problem.
Thanks.