Kommentarfunktion funktioinert bei einzelnen Usern nicht

<?php
    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. -->
<div id="commentsbox">
<?php if ( have_comments() ) : ?>
    <h3 id="comments"><?php comments_number('Keine Kommentare', 'Ein Kommentar', '% Kommentare' );?> bisher.</h3>






    <ol class="commentlist">
    <?php wp_list_comments(); ?>
    </ol>


    <div class="comment-nav clearfix">
        <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 ( comments_open() ) : ?>
        <!-- If comments are open, but there are no comments. -->


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




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




<?php if ( comments_open() ) : ?>
<div id="comment-form">
<div id="respond">


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




    <small><?php cancel_comment_reply_link(); ?></small>




<?php if ( get_option('comment_registration') && !is_user_logged_in() ) : ?>
<p>You must be <a href="<?php echo wp_login_url( 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 ( is_user_logged_in() ) : ?>


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


<label for="email">Mail <small><?php if ($req) echo "(benötigt)"; ?></small></label>
<input type="text" name="email" id="email" value="<?php echo esc_attr($comment_author_email); ?>" size="22" tabindex="2" <?php if ($req) echo "aria-required='true'"; ?> />


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




<?php endif; ?>


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


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


</form>


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


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