WCF::handleException() Unhandled exception: Call to undefined function wcf\util\bcadd()

#0 /var/www/wcfan.de/httpdocs/wcf/lib/data/infopages/InfoPages.class.php(345): wcf\util\InfoPagesSteamIDUtil::convertIDToSteamID3('0:1:17419913')
#1 /var/www/wcfan.de/httpdocs/wcf/lib/page/HlstatsxTopPage.class.php(52): wcf\data\infopages\InfoPages->getAllHLstatsXTopDatas()
#2 /var/www/wcfan.de/httpdocs/wcf/lib/page/AbstractPage.class.php(276): wcf\page\HlstatsxTopPage->assignVariables()
#3 /var/www/wcfan.de/httpdocs/wcf/lib/page/AbstractPage.class.php(100): wcf\page\AbstractPage->show()
#4 /var/www/wcfan.de/httpdocs/wcf/lib/system/request/Request.class.php(58): wcf\page\AbstractPage->__run()
#5 /var/www/wcfan.de/httpdocs/wcf/lib/system/request/RequestHandler.class.php(139): wcf\system\request\Request->execute()
#6 /var/www/wcfan.de/httpdocs/index.php(10): wcf\system\request\RequestHandler->handle('wbb')
#7 {main}