Whats wrong with my input form custom .tpl.php file?

Hi,

could anyone tell me why i get a white screen when trying to make a custom form template?
here is the function in my template.php

function phptemplate_testtype_node_form($form) {
  global $user;
  $vars = array('user' => $user, 'form' => $form);
  $vars['street'] = drupal_render($form['street']);
  $vars['housenr'] = drupal_render($form['housenr']);
  // etc
  return _phptemplate_callback('testtype', $vars);
}

and here is my testtype.tpl.php

<div id="head" style="height:150px; border:2px dotted #000000">
  <div id="street" style="padding-left:10px; width:150px; float:left">
    <?php print $street; ?>
  </div>
  <div id="housenr" style="float:right; padding-right:10px; width:100px;">
    <?php print $housenr; ?>
  </div>
</div>

grtz,
tom