comments Warning: require error

A friend asked for help, and I am stumped. Usually I can figure these things out. On her single page post her comments template does not show.

this is the error message

Warning: require(/home/ntirado/public_html/leaveittoweaver/wp/wp-content/themes/simplex.1.3.1/simplex) [function.require]: failed to open stream: No such device in /home/ntirado/public_html/leaveittoweaver/wp/wp-includes/comment-template.php on line 666

Fatal error: require() [function.require]: Failed opening required '/home/ntirado/public_html/leaveittoweaver/wp/wp-content/themes/simplex.1.3.1/simplex' (include_path='.:/usr/lib/php:/usr/local/lib/php') in /home/ntirado/public_html/leaveittoweaver/wp/wp-includes/comment-template.php on line 666

This is the code for the comments.php template

<?php

// Do not delete these lines
if (!empty($_SERVER['SCRIPT_FILENAME']) && 'comments.php' == basename($_SERVER['SCRIPT_FILENAME']))
die ('Please do not load this page directly. Thanks!');

if ( post_password_required() ) { ?>
<p class="nocomments">This post is password protected. Enter the password to view comments.</p>
<?php
return;
}
?>

<!-- You can start editing here. -->

<?php if ( have_comments() ) : ?>
<div id="maintabdiv">
<ul id="tabnav">
<li><a href="#comments" class="tabs current">Comments (<?php comments_number('0','1','%');?>;)</a></li>
<li><a href="#trackbacks" class="tabs">Trackbacks</a></li>
</ul>

<?php if ( ! empty($comments_by_type['comment']) ) : ?>

<div id="comments" class="commentlist">
<ol class="commentlist">
<?php wp_list_comments('type=comment'); ?>
</ol>
</div>
<?php endif; ?>

<div id="trackbacks">
<ol class="commentlist">
<?php if ( ! empty($comments_by_type['pings']) ) : ?>
<?php wp_list_comments('type=pings'); ?>
<?php else : ?>
<li>There are no trackbacks for this post yet.</li>
<?php endif; ?>
</ol>
</div>
</div>

<div class="navigation">
<div class="alignleft"><?php previous_comments_link() ?></div>
<div class="alignright"><?php next_comments_link() ?></div>
</div>

<?php else : // this is displayed if there are no comments so far ?>

<?php if ('open' == $post->comment_status) : ?>
<!-- If comments are open, but there are no comments. -->

<?php else : // comments are closed ?>
<!-- If comments are closed. -->
<p class="nocomments">Comments are closed.</p>

<?php endif; ?>
<?php endif; ?>

<?php if ('open' == $post->comment_status) : ?>

<div id="respond">

<h3><?php comment_form_title( 'Leave a Reply', 'Leave a Reply to %s' ); ?></h3>

<div class="cancel-comment-reply">
<small><?php cancel_comment_reply_link(); ?></small>
</div>

<?php if ( get_option('comment_registration') && !$user_ID ) : ?>
<p>You must be <a href="<?php echo get_option('siteurl'); ?>/wp-login.php?redirect_to=<?php echo urlencode(get_permalink()); ?>">logged in</a> to post a comment.</p>
<?php else : ?>

<form action="<?php echo get_option('siteurl'); ?>/wp-comments-post.php" method="post" id="commentform">

<?php if ( $user_ID ) : ?>

<p>Logged in as <a href="<?php echo get_option('siteurl'); ?>/wp-admin/profile.php"><?php echo $user_identity; ?></a>. <a href="<?php echo wp_logout_url(get_permalink()); ?>" title="Log out of this account">Log out &raquo;</a></p>

<?php else : ?>

<p><input type="text" name="author" id="author" value="<?php echo $comment_author; ?>" size="22" tabindex="1" <?php if ($req) echo "aria-required='true'"; ?> />
<label for="author"><small>Name <?php if ($req) echo "(required)"; ?></small></label></p>

<p><input type="text" name="email" id="email" value="<?php echo $comment_author_email; ?>" size="22" tabindex="2" <?php if ($req) echo "aria-required='true'"; ?> />
<label for="email"><small>Mail (will not be published) <?php if ($req) echo "(required)"; ?></small></label></p>

<p><input type="text" name="url" id="url" value="<?php echo $comment_author_url; ?>" size="22" tabindex="3" />
<label for="url"><small>Website</small></label></p>

<?php endif; ?>

<!--<p><small><strong>XHTML:</strong> You can use these tags: <code><?php echo allowed_tags(); ?></code></small></p>-->

<p><textarea name="comment" id="comment" cols="100%" rows="10" tabindex="4"></textarea></p>

<p><input name="submit" type="submit" id="submit" tabindex="5" value="Submit Comment" />
<?php comment_id_fields(); ?>
</p>
<?php do_action('comment_form', $post->ID); ?>

</form>

<?php endif; // If registration required and not logged in ?>
</div>

<?php endif; // if you delete this the sky will fall on your head ?>

and onto the single post code ?? just to cover my bases

<?php get_header(); ?>
<div id="main">
<div id="content" class="narrowcolumn">

<?php if (have_posts()) : while (have_posts()) : the_post(); ?>

<div class="post" id="post-<?php the_ID(); ?>">
<h2><?php the_title(); ?></h2>

<div class="entry">
<?php the_content('<p class="serif">Read the rest of this entry &raquo;</p>'); ?>

<?php wp_link_pages(array('before' => '<p><strong>Pages:</strong> ', 'after' => '</p>', 'next_or_number' => 'number')); ?>
<?php the_tags( '<p class="postmetadata">Tags: ', ', ', '</p>'); ?>

<p class="postmetadata2">
<small>
This entry was posted
<?php /* This is commented, because it requires a little adjusting sometimes.
You'll need to download this plugin, and follow the instructions:
https://binarybonsai.com/archives/2004/08/17/time-since-plugin/ */
/* $entry_datetime = abs(strtotime($post->post_date) - (60*120)); echo time_since($entry_datetime); echo ' ago'; */ ?>
on <?php the_time('l, F jS, Y') ?> at <?php the_time() ?>
and is filed under <?php the_category(', ') ?>.
You can follow any responses to this entry through the <?php post_comments_feed_link('RSS 2.0'); ?> feed.

<?php if (('open' == $post-> comment_status) && ('open' == $post->ping_status)) {
// Both Comments and Pings are open ?>
You can <a href="#respond">leave a response</a>, or <a href="<?php trackback_url(); ?>" rel="trackback">trackback</a> from your own site.

<?php } elseif (!('open' == $post-> comment_status) && ('open' == $post->ping_status)) {
// Only Pings are Open ?>
Responses are currently closed, but you can <a href="<?php trackback_url(); ?> " rel="trackback">trackback</a> from your own site.

<?php } elseif (('open' == $post-> comment_status) && !('open' == $post->ping_status)) {
// Comments are open, Pings are not ?>
You can skip to the end and leave a response. Pinging is currently not allowed.

<?php } elseif (!('open' == $post-> comment_status) && !('open' == $post->ping_status)) {
// Neither Comments, nor Pings are open ?>
Both comments and pings are currently closed.

<?php } edit_post_link('Edit this entry','','.'); ?>

</small>
</p>

</div>

</div>

<?php comments_template('', true); ?>

<?php endwhile; else: ?>

<p>Sorry, no posts matched your criteria.</p>

<?php endif; ?>

</div>
<?php get_sidebar(); ?>
</div>

<?php get_footer(); ?>