Fatal error in one of the languages

Hi,
I have a Drupal 7.18 installation with i18 7x-1.7, and many more modules; this is a finished project that is already in production since some weeks ago. The site has 4 active languages: spanish, english, french and arabic, with translated content in all of them.

The problem is that when you try to change to FRENCH only, the following error appears. It happens with ANY piece of french content.

I would be very grateful if you could help me solve this problem or give me some clue about this issue.
Ask me if you need more info too, since I can not imagine exactly what kind of info should I provide additionally.

Thanks.

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] => Attachments added to other displays to achieve multiple views in the same view. [:context] => ) in locale() (line 684 of D:\www\alfatorres\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] => %type: !message in %function (line %line of %file). [:context] => ) in locale() (line 684 of D:\www\alfatorres\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 D:\www\alfatorres\includes\session.inc).

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] => 205103997250d4643e200253.20471253 ) in lock_release_all() (line 269 of D:\www\alfatorres\includes\lock.inc).