zeitgeist-y

I can’t get this solution to work?! This is how my author.php currently looks like:

—————————
<?php get_header(); ?>

<div id=”content”>

<?php
if(isset($_GET[‘author_name’])) :
$curauth = get_userdatabylogin($author_name);
else :
$curauth = get_userdata($author);
endif;
?>

<h3>You’re currently viewing <?php echo $curauth->user_firstname; ?> <?php echo $curauth->user_lastname; ?>’s page of posts:</h3>

</div>

<?php get_sidebar(); ?>

<?php get_footer(); ?>
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I can’t even explain my problem. Have a look at the site:
http://zeitgeist.collectanea.org