[Plugin: Wp-postratings]Not work

I install the plugin Wp-postratings and add this code <?php if(function_exists(‘the_ratings’)) { the_ratings(); } ?> below <?php the_content(‘<p class="serif">Read the rest of this entry &raquo;</p>’); ?> in the single.php for my posts,but it doesn’t work , no ratings appear.See my post here.