Put next/previous post links at Top of page

My blog is Table for Five. I would like to add navigation links to my previous and next posts at the top of the single post page. I searched here and found this code:

<div class=”navigation”>
<div class=”alignleft”><?php previous_post(‘« %’,”,’yes’) ?></div>
<div class=”alignright”><?php next_post(‘ % »’,”,’yes’) ?></div>

I can get it to work when I insert it into single.php at the bottom just above <?php get_footer(); ?>, but when I try to put it at the top just under <?php get_header(); ?>, the links don’t appear. Am I putting the code in the wrong place? Or is there something else I’m missing? Thank you!