Thread:Extension talk:UserMerge/Mediawiki 1.22

I'm getting the following error:

[d473036b] /Special:UserMerge Exception from line 376 of /root/w/includes/SpecialPage.php: Call to undefined method UserMerge::getPageTitle Backtrace:
 * 1) 0 /root/w/extensions/UserMerge/UserMerge_body.php(128): SpecialPage->__call(string, array)
 * 2) 1 /root/w/extensions/UserMerge/UserMerge_body.php(128): UserMerge->getPageTitle
 * 3) 2 /root/w/includes/SpecialPage.php(631): UserMerge->execute(NULL)
 * 4) 3 /root/w/includes/SpecialPageFactory.php(488): SpecialPage->run(NULL)
 * 5) 4 /root/w/includes/Wiki.php(298): SpecialPageFactory::executePath(Title, RequestContext)
 * 6) 5 /root/w/includes/Wiki.php(602): MediaWiki->performRequest
 * 7) 6 /root/w/includes/Wiki.php(467): MediaWiki->main
 * 8) 7 /root/w/index.php(49): MediaWiki->run
 * 9) 8 {main}