Broken Page Navigation (except archives)

I have set my “Blog pages show” to 3 posts (temporarily, to figure this out).

http://www.amymahon.com/category/work/

You’ll see that you can easily scroll through the posts using the bottom navigation.

The problem happens here:
http://www.amymahon.com/

And here
http://www.amymahon.com/work/

— It doesn’t appear to be related to permalinks though as I’ve changed it back to default and I’m still getting the same problem. Basically the URL reroutes to /page/3 or whatever, but the content on the page is still the same.

I guess this means, then, that it’s a template problem, but I just can’t see where I went wrong.

<?php
/*
Template Name: Work
*/
?>

<?php get_header(); ?>

	<?php query_posts('cat=7&showposts=9'); ?>
		<?php if (have_posts()) : ?>
		<?php while (have_posts()) : the_post(); ?>
		     <!-- post stuff here -->
		<?php endwhile; ?>
			<div class="navigation">
			<div class="alignleft"><?php posts_nav_link('','','&laquo; Previous Entries') ?></div>
			<div class="alignright"><?php posts_nav_link('','Next Entries &raquo;','') ?></div>
			</div>

		<?php else : ?>

		<h2 class="center">Not Found</h2>
		<p class="center">Sorry, but you are looking for something that isn't here.</p>

		<?php endif; ?>
<?php get_sidebar(); ?>
<?php get_footer(); ?>

That’s the code for my “work” template that I have set the work page to display.