[Plugin: Navigable] Error when getting sub-navigation of a particular element:

Hi,

The plugin works great!

I’m getting an error when trying to get a sub-navigation of a particular element.

Here is my code:

<?php $nav = new NavigableWP('Main Navigation'); ?>
<?php if ($sub_nav = $nav->find_branch(14)): ?>

<ul>
<?php foreach ($sub_nav as $elem): ?>
<li class="nav-item<?php $elem->if_active('-current'); ?>"><a>url; ?>"><?php echo $elem->title; ?></a>
<?php endforeach; ?>
</ul>
<?php endif; ?>

The error:
Fatal error: Call to undefined method NavigableWP::find_branch(…

http://wordpress.org/extend/plugins/navigable/