Query Problem

All,

I’m running a query to return a list of child pages, the related excerpt and featured image thumbnail. The result looks like the following:

Preview

As you can see, the list returned isn’t sorted alphabetically, while the side bar is. My code is as follows:

+++++++++++++++++++++++++++++++

<h2><?php the_title(); ?></h2>
    <?php $this_page_id=$wp_query->post->ID; ?>

	<?php query_posts(array('order' => 'ASC','showposts' => 20, 'post_parent' => $this_page_id, 'post_type' => 'page')); while (have_posts()) { the_post(); ?>
		<!--begin profile-->
                     <div class="postprofile">
                        <div class="postprofile_photo">
                            <?php if ( has_post_thumbnail() ) {
the_post_thumbnail();
} else { ?>
<img src="<?php bloginfo('template_directory'); ?>/imgs/default_thumbnail.gif" alt="No photo available" title="No photo available" />
<?php } ?>
                        </div>
                        <div class="postprofile_text">
                            <h4><?php the_title(); ?></h4>
                            <?php the_excerpt(); ?>
        <p><a href="<?php echo get_permalink(); ?>" title="View profile">View profile</a></p>
                        </div>
                        <div class="rien"></div>
                     </div>
                     <!--end profile-->

	 <?php } ?>

+++++++++++++++++++++++++++++++

How can I modify the code to have the list display alphabetically by title?

Thanks in advance.