Topic on Extension talk:RefHelper

After installation of RefHelper on Mediawiki 1.17.0 (from snapshot) any attempt to edit page gives this:

Detected bug in an extension! Hook RefSearch::newArticleHook has invalid call signature; Parameter 1 to RefSearch::newArticleHook() expected to be a reference, value given Backtrace:

1. 0 /var/www/slwiki/includes/EditPage.php(313): wfRunHooks('AlternateEdit', Array)
2. 1 /var/www/slwiki/includes/EditPage.php(296): EditPage->edit()
3. 2 /var/www/slwiki/includes/Wiki.php(522): EditPage->submit()
4. 3 /var/www/slwiki/includes/Wiki.php(69): MediaWiki->performAction(Object(OutputPage), Object(Article), Object(Title), Object(User), Object(WebRequest))
5. 4 /var/www/slwiki/index.php(114): MediaWiki->performRequestForTitle(Object(Title), Object(Article), Object(OutputPage), Object(User), Object(WebRequest))
6. 5 {main}

What it may be?