Navigation links not visible in tinytheme mod.

I’m trying to modify Tinytheme. I’d like to change the navigation so it shows the name of the previous post instead of “Previous Entry” (and likewise for “Next Entry.”) I thought it would be as easy as removing the following code from index.php:


<p class="nav"><span class="prev"><?php posts_nav_link( '', '', __('« Previous Entry','bnTiny') ) ?></span>
<span class="next"><?php posts_nav_link( '', __('Next Entry »','bnTiny'), '' ) ?></span></p>


…and replacing it with the following from the WP Codex…


<?php previous_post('&laquo; &laquo; %', '', 'yes'); ?>
| <?php next_post('% &raquo; &raquo; ', '', 'yes'); ?>


…but no dice. (I only get the “|”… nothing else) (note: I’m not worried about the style right now, just want to get the PHP stuff working…)

What did I do wrong?… What’s the right code? Thanks in advance!