Internal error

[4bf6275d4dc5f7902af2b942] /wiki/Special:CreateProperty Error from line 99 of /var/www/html/w/extensions/PageForms/specials/PF_CreateProperty.php: Call to a member function getDatatypeLabels() on null

Backtrace:

#0 /var/www/html/w/extensions/PageForms/specials/PF_CreateProperty.php(22): PFCreateProperty->printCreatePropertyForm()
#1 /var/www/html/w/includes/specialpage/SpecialPage.php(600): PFCreateProperty->execute()
#2 /var/www/html/w/includes/specialpage/SpecialPageFactory.php(635): SpecialPage->run()
#3 /var/www/html/w/includes/MediaWiki.php(307): MediaWiki\SpecialPage\SpecialPageFactory->executePath()
#4 /var/www/html/w/includes/MediaWiki.php(947): MediaWiki->performRequest()
#5 /var/www/html/w/includes/MediaWiki.php(547): MediaWiki->main()
#6 /var/www/html/w/index.php(53): MediaWiki->run()
#7 /var/www/html/w/index.php(46): wfIndexMain()
#8 {main}