MediaWiki internal error.

Original exception: exception 'DBQueryError' with message 'A database error has occurred
Query: SELECT page_title, page_namespace
FROM `wiki_depage` FORCE INDEX (page_random)
WHERE page_namespace IN ( 0 )
AND page_is_redirect = 0
AND page_random >= 0.700994532002

ORDER BY page_random LIMIT 1
Function: RandomPage::selectRandomPageFromDB
Error: 1033 Incorrect information in file: './usr_web4_1/wiki_depage.frm' (localhost)
' in /var/www/web4/html/includes/db/Database.php:636
Stack trace:
#0 /var/www/web4/html/includes/db/Database.php(591): Database->reportQueryError('Incorrect infor...', 1033, 'SELECT page_tit...', 'RandomPage::sel...', false)
#1 /var/www/web4/html/includes/specials/SpecialRandompage.php(101): Database->query('SELECT page_tit...', 'RandomPage::sel...')
#2 /var/www/web4/html/includes/specials/SpecialRandompage.php(61): RandomPage->selectRandomPageFromDB('0.700994532002')
#3 /var/www/web4/html/includes/specials/SpecialRandompage.php(42): RandomPage->getRandomTitle()
#4 /var/www/web4/html/includes/SpecialPage.php(539): RandomPage->execute(NULL)
#5 /var/www/web4/html/includes/Wiki.php(226): SpecialPage::executePath(Object(Title))
#6 /var/www/web4/html/includes/Wiki.php(59): MediaWiki->initializeSpecialCases(Object(Title), Object(OutputPage), Object(WebRequest))
#7 /var/www/web4/html/wiki(114): MediaWiki->initialize(Object(Title), NULL, Object(OutputPage), Object(User), Object(WebRequest))
#8 {main}

Exception caught inside exception handler: exception 'DBQueryError' with message 'A database error has occurred
Query: SELECT value,exptime FROM `wiki_deobjectcache` WHERE keyname='usr_web4_1-wiki_de:messages:de'
Function: MediaWikiBagOStuff::_doquery
Error: 1033 Incorrect information in file: './usr_web4_1/wiki_deobjectcache.frm' (localhost)
' in /var/www/web4/html/includes/db/Database.php:636
Stack trace:
#0 /var/www/web4/html/includes/db/Database.php(591): Database->reportQueryError('Incorrect infor...', 1033, 'SELECT value,ex...', 'MediaWikiBagOSt...', false)
#1 /var/www/web4/html/includes/BagOStuff.php(454): Database->query('SELECT value,ex...', 'MediaWikiBagOSt...')
#2 /var/www/web4/html/includes/BagOStuff.php(324): MediaWikiBagOStuff->_doquery('SELECT value,ex...')
#3 /var/www/web4/html/includes/BagOStuff.php(240): SqlBagOStuff->_query('SELECT value,ex...', 'usr_web4_1-wiki...')
#4 /var/www/web4/html/includes/MessageCache.php(245): SqlBagOStuff->get('usr_web4_1-wiki...')
#5 /var/www/web4/html/includes/MessageCache.php(589): MessageCache->load('de')
#6 /var/www/web4/html/includes/MessageCache.php(526): MessageCache->getMsgFromNamespace('Databaseerror', 'de')
#7 /var/www/web4/html/includes/GlobalFunctions.php(583): MessageCache->get('databaseerror', true, false)
#8 /var/www/web4/html/includes/GlobalFunctions.php(548): wfMsgGetKey('databaseerror', true, false, true)
#9 /var/www/web4/html/includes/Exception.php(70): wfMsgReal('databaseerror', Array)
#10 /var/www/web4/html/includes/db/Database.php(2617): MWException->msg('databaseerror', 'Database error')
#11 /var/www/web4/html/includes/Exception.php(201): DBQueryError->getPageTitle()
#12 /var/www/web4/html/includes/Exception.php(164): MWException->htmlHeader()
#13 /var/www/web4/html/includes/Exception.php(183): MWException->reportHTML()
#14 /var/www/web4/html/includes/Exception.php(269): MWException->report()
#15 /var/www/web4/html/includes/Exception.php(327): wfReportException(Object(DBQueryError))
#16 [internal function]: wfExceptionHandler(Object(DBQueryError))
#17 {main}