Fatal error: PHP error in file /var/www/web151/htdocs/wcf/lib/page/HangmanPlayPage.class.php (98): Non-static method Hangman::zufallswort() should not be called statically, assuming $this from incompatible context

Information:

error message: PHP error in file /var/www/web151/htdocs/wcf/lib/page/HangmanPlayPage.class.php (98): Non-static method Hangman::zufallswort() should not be called statically, assuming $this from incompatible context
error code: 0
file: /var/www/web151/htdocs/wcf/lib/system/WCF.class.php (255)
php version: 5.4.45
wcf version: 1.0.11 pl 4 (Horizon)
date: Sun, 15 Sep 2019 20:49:59 +0000
request: /index.php?page=HangmanPlay&s=f517a3a8a3de534f37441723b53cbedf1ca428a6
referer:

Stacktrace:

#0 /var/www/web151/htdocs/wcf/lib/page/HangmanPlayPage.class.php(98): WCF::handleError(2048, 'Non-static meth...', '/var/www/web151...', 98, Array)
#1 /var/www/web151/htdocs/wcf/lib/page/AbstractPage.class.php(35): HangmanPlayPage->readParameters()
#2 /var/www/web151/htdocs/wcf/lib/util/RequestHandler.class.php(63): AbstractPage->__construct()
#3 /var/www/web151/htdocs/wcf/lib/util/RequestHandler.class.php(91): RequestHandler->__construct('HangmanPlay', Array, 'page')
#4 /var/www/web151/htdocs/index.php(8): RequestHandler::handle(Array)
#5 {main}