[Plugin: Efficient Related Posts] How to add if function exists to avoid theme error?

<?php wp_related_posts(array(‘title’=>’Most Related Post’, ‘num_to_display’=>5)) ; ?>

The page shows blank, I don’t know what i am doing wrong here

<?php if (function_exists(‘wp_related_posts’)) { wp_related_posts(array(‘title’=>’Most Related Post’, ‘num_to_display’=>5))(); } ?><?php endif; ?>

http://wordpress.org/extend/plugins/efficient-related-posts/