print image gallery in table with dompdf [#961600]

HI there,
I like to pdf some nodes via a views list of nodes - it's working..!:-) BUT.. in some nodes are image galleries. Dompdf don't support floats yet.. in version 0.5
In oder to that I try to print the images in a table. It's working for an single node, but is not working for my "node list" (display full nodes - with commments).
If I pdf the node list I got this error:

array_chunk() expects parameter 1 to be array, null given in /is/htdocs/xx/themes/xx/print_pdf.tpl.php in Zeile 46.
Invalid argument supplied for foreach() in /is/htdocs/xx/themes/xx/print_pdf.tpl.php in Zeile 56.

What could be the cause?

This is my print_pdf.tpl.php

<?php
// $Id: print.blog_public.tpl.php,v 1.8.2.17 2010/08/18 00:33:34 xx Exp $

/**
 * @file
 * Default print module template
 *
 * @ingroup print
 */
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="<?php print $print['language']; ?>" xml:lang="<?php print $print['language']; ?>">
  <head>
    <?php print $print['head']; ?>
    <?php print $print['base_href']; ?>
    <?php print $print['scripts']; ?>
    <?php print $print['sendtoprinter']; ?>
    <?php print $print['css']; ?>
  </head>
  <body>
 <?php  $node = $print['node']; ?>
   <div id="page-print">
   <?php if (!empty($print['message'])) {
      print '<div class="print-message">'. $print['message'] .'</div><p />';
    } ?>
    <div class="print-logo"><?php print $print['logo']; ?></div>
    <div class="print-site_name"><?php print $print['site_name']; ?></div>
    <p />
    <hr class="print-hr" />
    <div class="print-content"><?php print $print['content']; ?></div>
<?php    
  $columns = 3;     
  $items = array(); 
 $items = $node->field_image_upload;
$result = count($items);

$rows = array_chunk($items, $columns);
?>
<?php if (!$field_empty) : ?>

<table class="mini-gallery">
  <tbody>
       <?php foreach ($rows as $row_number => $columns): ?>
      <?php
        $row_class = 'row-' . ($row_number + 1);
        if ($row_number == 0) {
          $row_class .= ' row-first';
        }
        if (count($rows) == ($row_number + 1)) {
          $row_class .= ' row-last';
        }
      ?>
          <tr class="<?php print $row_class; ?>">
        <?php foreach ($columns as $column_number => $item): ?>
          <td class="<?php print 'col-'. ($column_number + 1); ?>">
            <div class="photo-image"><?php print $item['view']; ?></div>
            <div class="photo-title"><?php print $item['data']['title']; ?><div>
          </td>
        <?php endforeach; ?>
      </tr>
    <?php endforeach; ?>
  </tbody>
</table>
<?php endif; ?>    
  <hr class="print-hr" />
</div>
  </body>
</html>