Was ist hier dran falsch? the_content_rss ?

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






<div class="post" id="post-<?php the_ID(); ?>" style="margin-bottom: 0px;">
<div class="p-head">


<br><br>


<div id="mainpall">


<div id="mainpads">
Ads
</div>


<div id="mainplinks">


<p class="p-date"><?php the_time('l') ?>, <?php the_time('d') ?>. <?php the_time('F') ?> <?php the_time('Y') ?></p>






<h2><?php the_title(); ?></h2><br>
<div class="post-ratings-text">
<?php if(function_exists('the_ratings')) { the_ratings(); } ?>  
</div>


<br><br>


<div class="inbox">
<?php $posts = get_posts("cat=4&numberposts=1&orderby=post_date&order=DESC"); foreach($posts as $post) : ?>    
  <a href="<?php the_permalink(); ?>"><?php the_title(); ?></a><br><?php the_content_rss('', TRUE, '', 20); ?>
<?php endforeach; ?>
</div>




<b><?php the_title(); ?><br></b>


<div class="p-con">
<?php the_content(''); ?>
</div>


<br><br>


<div class="comment-box"><a href="#kommentieren">
<?php comments_number('kein Kommentar', '1 Kommentar', '% Kommentare' ); ?> zu
<br>
<b><?php the_title(); ?></b> <br> Auch Kommentieren?</a> 
</div>




<br>
<?php if (function_exists('the_tags')) { ?> <?php the_tags('<div class="p-tag">Schlagwort -<b>  ', ', ', '</b></div>'); ?> <?php } ?>
<br><br><br>


<?php similar_posts(); ?>








</div></div></div></div></div>


 






<?php comments_template(); ?>
<?php endwhile; else: ?>


<p>Sorry, nichts gefunden!</p>


<?php endif; ?>
<?php get_footer(); ?>