Because I am very particular about how to do things in WordPress when it comes to looping, I couldn’t help but want to post a better way to do the above loop in your question as seeing the way you’ve done it looks like a lot of unnecessary work for yourself.
You already answered your own question but for the sake of being able to use the function the_excerpt() I’ve rewritten the above code to work using the WP_Query object instead which I believe is a better way of going about loop related matters (not to mention easier). You really only need to use manual queries like that when you want to query something the WP_Query class cannot.
<?php
$args = array('post_parent' => 64, 'orderby' => 'title', 'order' => 'ASC', 'post_type' => 'page', 'post_status' => 'publish');
$child_pages = new WP_Query($args);
?>
<?php if ($child_pages->have_posts()): ?>
<?php while($child_pages->have_posts()): $child_pages->the_post(); ?>
<div class="memberHover" id="member-<?php the_ID(); ?>">
<div><h4><?php the_title(); ?></h4>
<p><?php the_excerpt(); ?></p>
</div><?php echo get_the_post_thumbnail($post->ID, '312,156'); ?>
</div>
<?php endwhile; ?>
<?php endif; ?>