WordPress Page Navigation Issue

On this page here WordPress won’t display the “Next” and “Previous” page navigation even though I have more than 3 posts (3 is the limit I put in the options) under that category.

Here’s the code for that page:

<?php $my_query = new WP_Query('cat=5');
  while ($my_query->have_posts()) : $my_query->the_post();
  $do_not_duplicate = $post->ID;?>
  <div class="titles">
  <h2><a href="<?php the_permalink() ?>" rel="bookmark"><?php the_title(); ?></a><br />
<?php the_time('m.d.Y'); ?></h2>
  </div>
		<?php the_content(__('(more...)')); ?>
  <?php endwhile; ?>
 <?php next_posts_link('&laquo; Previous Entries') ?>
 <?php previous_posts_link('Next Entries &raquo;') ?>

Is there any reason to why this doesn’t display the page navigation?

Thanks,
Eric Huang