Articles App Plugin - Fatal Error

Hi guys, i installed this plugin

http://stackideas.com/apps/item/8-articles

When i try to publish an article from within the joomla backend i obtain the error below and no EasySocial stream item is generated

Fatal error: Class 'ContentHelperRoute' not found in /home/public_html/mysite.com/plugins/content/easysocial/easysocial.php on line 371

How can i fix this ? What can be the cause ?

Thanks !