MediaWiki internal error.

Original exception: [2383151ebc09993f70bd2ce4] /Special:WhatLinksHere/Talk:A_Plea_for_a_Return_to_Diff%C3%A9rance MWUnknownContentModelException from line 306 of /home/riotawfb/nosubject.com/includes/content/ContentHandler.php: The content model 'flow-board' is not registered on this wiki.
See https://www.mediawiki.org/wiki/Content_handlers to find out which extensions handle this content model.
Backtrace:
#0 /home/riotawfb/nosubject.com/includes/content/ContentHandler.php(243): ContentHandler::getForModelID(string)
#1 /home/riotawfb/nosubject.com/includes/Title.php(4984): ContentHandler::getForTitle(Title)
#2 /home/riotawfb/nosubject.com/includes/skins/SkinTemplate.php(1142): Title->getPageLanguage()
#3 /home/riotawfb/nosubject.com/includes/skins/SkinTemplate.php(476): SkinTemplate->buildContentNavigationUrls()
#4 /home/riotawfb/nosubject.com/includes/skins/SkinTemplate.php(249): SkinTemplate->prepareQuickTemplate()
#5 /home/riotawfb/nosubject.com/includes/OutputPage.php(2388): SkinTemplate->outputPage()
#6 /home/riotawfb/nosubject.com/includes/MediaWiki.php(868): OutputPage->output(boolean)
#7 /home/riotawfb/nosubject.com/includes/MediaWiki.php(880): MediaWiki->{closure}()
#8 /home/riotawfb/nosubject.com/includes/MediaWiki.php(524): MediaWiki->main()
#9 /home/riotawfb/nosubject.com/index.php(42): MediaWiki->run()
#10 {main}

Exception caught inside exception handler: [2383151ebc09993f70bd2ce4] /Special:WhatLinksHere/Talk:A_Plea_for_a_Return_to_Diff%C3%A9rance MWUnknownContentModelException from line 306 of /home/riotawfb/nosubject.com/includes/content/ContentHandler.php: The content model 'flow-board' is not registered on this wiki.
See https://www.mediawiki.org/wiki/Content_handlers to find out which extensions handle this content model.
Backtrace:
#0 /home/riotawfb/nosubject.com/includes/content/ContentHandler.php(243): ContentHandler::getForModelID(string)
#1 /home/riotawfb/nosubject.com/includes/Title.php(4984): ContentHandler::getForTitle(Title)
#2 /home/riotawfb/nosubject.com/includes/skins/SkinTemplate.php(1142): Title->getPageLanguage()
#3 /home/riotawfb/nosubject.com/includes/skins/SkinTemplate.php(476): SkinTemplate->buildContentNavigationUrls()
#4 /home/riotawfb/nosubject.com/includes/skins/SkinTemplate.php(249): SkinTemplate->prepareQuickTemplate()
#5 /home/riotawfb/nosubject.com/includes/OutputPage.php(2388): SkinTemplate->outputPage()
#6 /home/riotawfb/nosubject.com/includes/exception/MWException.php(160): OutputPage->output()
#7 /home/riotawfb/nosubject.com/includes/exception/MWException.php(201): MWException->reportHTML()
#8 /home/riotawfb/nosubject.com/includes/exception/MWExceptionHandler.php(73): MWException->report()
#9 /home/riotawfb/nosubject.com/includes/exception/MWExceptionHandler.php(149): MWExceptionHandler::report(MWUnknownContentModelException)
#10 /home/riotawfb/nosubject.com/includes/MediaWiki.php(551): MWExceptionHandler::handleException(MWUnknownContentModelException)
#11 /home/riotawfb/nosubject.com/index.php(42): MediaWiki->run()
#12 {main}