MediaWiki internal error.

Original exception: exception 'DBQueryError' with message 'A database error has occurred
Query: SELECT page_id, page_namespace, page_title, page_is_redirect, page_len FROM `page` WHERE (page_namespace=0 AND page_title IN('Robin_Gallowglass', 'Rónán_Meablach', 'Gabriel_of_Maccuswell', 'Zaneta_Angiolieri', 'Lorenz_Greylever', 'Raffaella_Mascolo', 'Robin_Gallowglass', 'Ælfwine_Akeworthe', 'Jana_von_Drachenklaue', 'Order_of_Precedence', 'Ian_Raven_of_Tadcaster', 'Kingdom_Web_Minister', 'Lucan_von_Drachenklaue')) OR (page_namespace=11 AND page_title IN('EKwebministers'))
Function: Parser::replaceLinkHolders
Error: 2002 Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (111) (localhost)
' in /usr/share/mediawiki1.7/includes/db/Database.php:606
Stack trace:
#0 /usr/share/mediawiki1.7/includes/db/Database.php(561): Database->reportQueryError('Can't connect t...', 2002, 'SELECT page_id,...', 'Parser::replace...', false)
#1 /usr/share/mediawiki1.7/includes/parser/Parser.php(4102): Database->query('SELECT page_id,...', 'Parser::replace...')
#2 /usr/share/mediawiki1.7/includes/parser/Parser.php(334): Parser->replaceLinkHolders('<div>?<table wi...')
#3 /usr/share/mediawiki1.7/includes/OutputPage.php(405): Parser->parse('{{Populace?|pho...', Object(Title), Object(ParserOptions), true, true, 19040)
#4 /usr/share/mediawiki1.7/includes/OutputPage.php(391): OutputPage->addWikiTextTitle('{{Populace?|pho...', Object(Title), true, true)
#5 /usr/share/mediawiki1.7/includes/OutputPage.php(500): OutputPage->addWikiTextTitleTidy('{{Populace?|pho...', Object(Title), true)
#6 /usr/share/mediawiki1.7/includes/DifferenceEngine.php(313): OutputPage->addWikiTextTidy('{{Populace?|pho...')
#7 /usr/share/mediawiki1.7/includes/DifferenceEngine.php(271): DifferenceEngine->renderNewRevision()
#8 /usr/share/mediawiki1.7/includes/Article.php(729): DifferenceEngine->showDiffPage(false)
#9 /usr/share/mediawiki1.7/includes/Wiki.php(437): Article->view()
#10 /usr/share/mediawiki1.7/includes/Wiki.php(59): MediaWiki->performAction(Object(OutputPage), Object(Article), Object(Title), Object(User), Object(WebRequest))
#11 /var/lib/mediawiki1.7/index.php(93): MediaWiki->initialize(Object(Title), Object(Article), Object(OutputPage), Object(User), Object(WebRequest))
#12 {main}

Exception caught inside exception handler: exception 'DBUnexpectedError' with message 'Error in fetchObject(): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (111) (localhost)' in /usr/share/mediawiki1.7/includes/db/Database.php:735
Stack trace:
#0 /usr/share/mediawiki1.7/includes/db/Database.php(2620): Database->fetchObject(false)
#1 /usr/share/mediawiki1.7/includes/LinkBatch.php(98): ResultWrapper->fetchObject()
#2 /usr/share/mediawiki1.7/includes/LinkBatch.php(78): LinkBatch->addResultToCache(Object(LinkCache), Object(ResultWrapper))
#3 /usr/share/mediawiki1.7/includes/LinkBatch.php(68): LinkBatch->executeInto(Object(LinkCache))
#4 /usr/share/mediawiki1.7/includes/Skin.php(208): LinkBatch->execute()
#5 /usr/share/mediawiki1.7/includes/Skin.php(184): Skin->preloadExistence()
#6 /usr/share/mediawiki1.7/includes/SkinTemplate.php(106): Skin->initPage(Object(OutputPage))
#7 /usr/share/mediawiki1.7/skins/MonoBook.php(24): SkinTemplate->initPage(Object(OutputPage))
#8 /usr/share/mediawiki1.7/includes/SkinTemplate.php(151): SkinMonoBook->initPage(Object(OutputPage))
#9 /usr/share/mediawiki1.7/includes/OutputPage.php(821): SkinTemplate->outputPage(Object(OutputPage))
#10 /usr/share/mediawiki1.7/includes/Exception.php(150): OutputPage->output()
#11 /usr/share/mediawiki1.7/includes/Exception.php(174): MWException->reportHTML()
#12 /usr/share/mediawiki1.7/includes/Exception.php(260): MWException->report()
#13 /usr/share/mediawiki1.7/includes/Exception.php(294): wfReportException(Object(DBQueryError))
#14 [internal function]: wfExceptionHandler(Object(DBQueryError))
#15 {main}