MediaWiki internal error.

Original exception: exception 'MWException' with message 'Detected bug in an extension! Hook fnEditWarning_edit has invalid call signature; Parameter 1 to fnEditWarning_edit() expected to be a reference, value given' in /home/formationn/www/mercurewiki/includes/Hooks.php:184
Stack trace:
#0 /home/formationn/www/mercurewiki/includes/EditPage.php(313): wfRunHooks('AlternateEdit', Array)
#1 /home/formationn/www/mercurewiki/includes/EditPage.php(296): EditPage->edit()
#2 /home/formationn/www/mercurewiki/includes/Wiki.php(533): EditPage->submit()
#3 /home/formationn/www/mercurewiki/includes/Wiki.php(69): MediaWiki->performAction(Object(OutputPage), Object(Article), Object(Title), Object(User), Object(WebRequest))
#4 /home/formationn/www/mercurewiki/index.php(114): MediaWiki->performRequestForTitle(Object(Title), Object(Article), Object(OutputPage), Object(User), Object(WebRequest))
#5 /home/formationn/www/mercurewiki/index.php5(1): require('/home/formation...')
#6 {main}

Exception caught inside exception handler: exception 'DBConnectionError' with message 'DB connection error: Unknown error (formationnmercur.mysql.db)' in /home/formationn/www/mercurewiki/includes/db/Database.php:626
Stack trace:
#0 /home/formationn/www/mercurewiki/includes/db/LoadBalancer.php(679): DatabaseBase->reportConnectionError('Unknown error (...')
#1 /home/formationn/www/mercurewiki/includes/db/LoadBalancer.php(452): LoadBalancer->reportConnectionError(Object(DatabaseMysql))
#2 /home/formationn/www/mercurewiki/includes/BagOStuff.php(254): LoadBalancer->getConnection(-2)
#3 /home/formationn/www/mercurewiki/includes/BagOStuff.php(265): SqlBagOStuff->getDB()
#4 /home/formationn/www/mercurewiki/includes/MessageCache.php(252): SqlBagOStuff->get('formationnmercu...')
#5 /home/formationn/www/mercurewiki/includes/MessageCache.php(606): MessageCache->load('fr')
#6 /home/formationn/www/mercurewiki/includes/MessageCache.php(545): MessageCache->getMsgFromNamespace('Internalerror', 'fr')
#7 /home/formationn/www/mercurewiki/includes/GlobalFunctions.php(781): MessageCache->get('internalerror', true, false)
#8 /home/formationn/www/mercurewiki/includes/GlobalFunctions.php(744): wfMsgGetKey('internalerror', true, false, true)
#9 /home/formationn/www/mercurewiki/includes/GlobalFunctions.php(644): wfMsgReal('internalerror', Array, true)
#10 /home/formationn/www/mercurewiki/includes/Exception.php(137): wfMsg('internalerror')
#11 /home/formationn/www/mercurewiki/includes/Exception.php(175): MWException->getPageTitle()
#12 /home/formationn/www/mercurewiki/includes/Exception.php(220): MWException->reportHTML()
#13 /home/formationn/www/mercurewiki/includes/Exception.php(325): MWException->report()
#14 /home/formationn/www/mercurewiki/includes/Exception.php(393): wfReportException(Object(MWException))
#15 [internal function]: wfExceptionHandler(Object(MWException))
#16 {main}