Thread:Extension talk:UserMerge/Fatal error: Call to undefined method User::getEditToken()

I have this error;

Fatal error: Call to undefined method User::getEditToken in /var/www/lighttpd/vhosts/www.liblfds.org/mediawiki/extensions/UserMerge/UserMerge_body.php on line 148

PHP 5.3.17 (cli) (built: Sep 17 2012 20:19:13) Product 	Version MediaWiki 	1.18.2 PHP 	5.3.17 (cgi-fcgi) PostgreSQL 	9.2.1