Internal error

[ZinrYx3OVIJ_NnFgeQQdrAAAAEw] /mw/index.php?title=Filter:Municipality&oldid=371 Error from line 122 of /home1/vilenya/public_html/mw/extensions/SemanticMediaWiki/src/DependencyValidator.php: Call to a member function getNamespace() on null

Backtrace:

#0 /home1/vilenya/public_html/mw/extensions/SemanticMediaWiki/src/MediaWiki/Hooks/ArticleViewHeader.php(71): SMW\DependencyValidator->hasArchaicDependencies(SMW\DIWikiPage)
#1 /home1/vilenya/public_html/mw/extensions/SemanticMediaWiki/src/MediaWiki/Hooks.php(675): SMW\MediaWiki\Hooks\ArticleViewHeader->process(Article, boolean, boolean)
#2 /home1/vilenya/public_html/mw/includes/Hooks.php(174): SMW\MediaWiki\Hooks->onArticleViewHeader(Article, boolean, boolean)
#3 /home1/vilenya/public_html/mw/includes/Hooks.php(202): Hooks::callHook(string, array, array, NULL)
#4 /home1/vilenya/public_html/mw/includes/page/Article.php(675): Hooks::run(string, array)
#5 /home1/vilenya/public_html/mw/includes/actions/ViewAction.php(68): Article->view()
#6 /home1/vilenya/public_html/mw/includes/MediaWiki.php(499): ViewAction->show()
#7 /home1/vilenya/public_html/mw/includes/MediaWiki.php(294): MediaWiki->performAction(Article, Title)
#8 /home1/vilenya/public_html/mw/includes/MediaWiki.php(865): MediaWiki->performRequest()
#9 /home1/vilenya/public_html/mw/includes/MediaWiki.php(515): MediaWiki->main()
#10 /home1/vilenya/public_html/mw/index.php(42): MediaWiki->run()
#11 {main}