Help adding code to comments.php per Author Highlight plugin

Highlighting comments worked for the main user before the upgrade (4 versions). Can someone help me with this?

I have the Author Highlight Plugin – http://plugins.trac.wordpress.org/wiki/AuthorHighlight – to use. And it says to add code into my comments.php. But where? ..and what does the “This is a comment” need to be?

I included my comments.php at the bottom.

Thanks in advance for your help!

FROM AUTHOR HIGHLIGHTS
You need to add this code to your comments.php file (in your theme’s directory):

<?php author_highlight(); ?>

It needs to be withing the loop for the comments, and you want to specify it so that it outputs into a class attribute. Something like this:
<div class=”<?php author_highlight(); ?>”>
This is a comment.
</div>

FROM MY COMMENTS.PHP FILE

<?php // Do not delete these lines
	if ('comments.php' == basename($_SERVER['SCRIPT_FILENAME']))
		die ('Please do not load this page directly. Thanks!');
        if (!empty($post->post_password)) { // if there's a password
            if ($_COOKIE['wp-postpass_' . COOKIEHASH] != $post->post_password) {  // and it doesn't match the cookie
				?>

				<p class="nocomments"><?php _e("This post is password protected. Enter the password to view comments."); ?><p>

				<?php
				return;
            }
        }

		/* This variable is for alternating comment background */
		$oddcomment = 'alt';
?>

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

<?php if ($comments) : ?>

	<h3 id="comments"><?php comments_number('No Responses', 'One Response', '% Responses' );?> to “<?php the_title(); ?>”</h3> 

	<ol class="commentlist">

	<?php foreach (array_reverse($comments) as $comment) : ?>

		<li class="<?php echo $oddcomment; ?>" id="comment-comment_ID()?php the_author_link() ?>">
			<div class="cmtinfo"><em>on <?php comment_date('d M Y') ?> at <?php comment_time() ?> <small class="commentmetadata"><a>" title=""> </a> <?php edit_comment_link('edit this','',''); ?></small></em><cite><?php comment_author_link() ?></cite></div>
			<?php if ($comment->comment_approved == '0') : ?>
			<em>Your comment is awaiting moderation.</em>
			<?php endif; ?>

			<?php comment_text() ?>			

	<?php /* Changes every other comment to a different class */
		if ('alt' == $oddcomment) $oddcomment = '';
		else $oddcomment = 'alt';
	?>

	<?php endforeach; /* end for each comment */ ?>

 <?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) : ?>

<h3 id="respond">Leave a Reply</h3>
<p><i>(Please note that Keshav reviews all comments and sharings and that they are subject to editing and posting at his discretion.)</i><p>

<?php if ( get_option('comment_registration') && !$user_ID ) : ?>
<p>You must be <a>/wp-login.php?redirect_to=<?php the_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>/wp-admin/profile.php"><?php echo $user_identity; ?></a>. <a>/wp-login.php?action=logout" title="<?php _e('Log out of this account') ?>">Logout »</a></p>

<?php else : ?>

<p>Testing</p>

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

<p><input type="text" class="text" name="email" id="email" value="<?php echo $comment_author_email; ?>" size="22" tabindex="2" />
<label for="email"><small>Mail (hidden) <?php if ($req) _e('(required)'); ?></small></label></p>

<p><input type="text" class="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: <?php echo allowed_tags(); ?></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" />
<input type="hidden" name="comment_post_ID" value="<?php echo $id; ?>" />
</p>

<?php do_action('comment_form', $post->ID); ?>

<p>Live Preview</p>
<p style="border: 1px solid #ccc;"><?php live_preview() ?></p>

</form>

<?php endif; // If registration required and not logged in ?>
<?php endif; // if you delete this the sky will fall on your head ?>

[Moderator Note: Please post code or markup snippets between backticks or use the code button. Or better still – use the pastebin. Your posted code may now have been damaged by the forum’s parser.]