Thread:Extension talk:RefHelper/Edit error

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?