MediaWiki internal error.

Original exception: exception 'DBQueryError' with message 'A database error has occurred
Query: SELECT rev_id,rev_page,rev_text_id,rev_timestamp,rev_comment,rev_user_text,rev_user,rev_minor_edit,rev_deleted,rev_len,rev_parent_id,page_namespace,page_title,page_latest FROM `page`,`revision` WHERE (rev_id=page_latest) AND (page_id=rev_page) AND page_namespace = '10' AND page_title = 'EKheralds' LIMIT 1
Function: Revision::fetchRow
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 rev_id,...', 'Revision::fetch...', false)
#1 /usr/share/mediawiki1.7/includes/db/Database.php(969): Database->query('SELECT rev_id,...', 'Revision::fetch...')
#2 /usr/share/mediawiki1.7/includes/Revision.php(236): Database->select(Array, Array, Array, 'Revision::fetch...', Array)
#3 /usr/share/mediawiki1.7/includes/Revision.php(165): Revision::fetchFromConds(Object(DatabaseMysql), Array)
#4 /usr/share/mediawiki1.7/includes/Revision.php(146): Revision::loadFromConds(Object(DatabaseMysql), Array)
#5 /usr/share/mediawiki1.7/includes/Revision.php(49): Revision::newFromConds(Array)
#6 /usr/share/mediawiki1.7/includes/parser/Parser.php(3104): Revision::newFromTitle(Object(Title))
#7 [internal function]: Parser->statelessFetchTemplate(Object(Title), Object(Parser))
#8 /usr/share/mediawiki1.7/includes/parser/Parser.php(3065): call_user_func(Array, Object(Title), Object(Parser))
#9 /usr/share/mediawiki1.7/includes/parser/Parser.php(3042): Parser->fetchTemplateAndTitle(Object(Title))
#10 /usr/share/mediawiki1.7/includes/parser/Parser.php(2929): Parser->getTemplateDom(Object(Title))
#11 /usr/share/mediawiki1.7/includes/parser/Preprocessor_DOM.php(915): Parser->braceSubstitution(Array, Object(PPFrame_DOM))
#12 /usr/share/mediawiki1.7/includes/parser/Parser.php(2674): PPFrame_DOM->expand(Object(PPNode_DOM), 0)
#13 /usr/share/mediawiki1.7/includes/parser/Parser.php(962): Parser->replaceVariables('{{Populace|phot...')
#14 /usr/share/mediawiki1.7/includes/parser/Parser.php(317): Parser->internalParse('{{Populace|phot...')
#15 /usr/share/mediawiki1.7/includes/OutputPage.php(405): Parser->parse('{{Populace|phot...', Object(Title), Object(ParserOptions), true, true, 6709)
#16 /usr/share/mediawiki1.7/includes/OutputPage.php(391): OutputPage->addWikiTextTitle('{{Populace|phot...', Object(Title), true, true)
#17 /usr/share/mediawiki1.7/includes/OutputPage.php(500): OutputPage->addWikiTextTitleTidy('{{Populace|phot...', Object(Title), true)
#18 /usr/share/mediawiki1.7/includes/DifferenceEngine.php(313): OutputPage->addWikiTextTidy('{{Populace|phot...')
#19 /usr/share/mediawiki1.7/includes/DifferenceEngine.php(271): DifferenceEngine->renderNewRevision()
#20 /usr/share/mediawiki1.7/includes/Article.php(729): DifferenceEngine->showDiffPage(false)
#21 /usr/share/mediawiki1.7/includes/Wiki.php(437): Article->view()
#22 /usr/share/mediawiki1.7/includes/Wiki.php(59): MediaWiki->performAction(Object(OutputPage), Object(Article), Object(Title), Object(User), Object(WebRequest))
#23 /var/lib/mediawiki1.7/index.php(93): MediaWiki->initialize(Object(Title), Object(Article), Object(OutputPage), Object(User), Object(WebRequest))
#24 {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}