Call to undefined method in articlesuggestions.php

I have just installed this and when viewing an article I get a white page with the following error message.

Fatal error: Call to undefined method JDatabaseMySQL::escape() in /home5/*****/public_html/*******/plugins/content/articlesuggestions/articlesuggestions.php on line 587

Does anyone know what this means and how to fix it? I have only enabled related articles on the plugin.

Thanks