the content type story might not exist (even more on custom installation profiles)

the content type story might not exist (even more on custom installation profiles)
but normally the content type could be removed from the content types
so .module line 137:
'#default_value' => variable_get("freelinking_nodetype", 'story'),
should be:

  $default_type = variable_get('freelinking_nodetype', NULL);
  //avoid look for a suitable type when isn't needed
  if (empty($default_type)) {
    $default_type = _wfk_find_suitable_default_type();
  }
  ...
    '#default_value' => $default_type, 

and:

function _wfk_find_suitable_default_type() {
  $types = node_get_types('types');
  $default_type = $types[0]->type; //just in case we have to give up (there has to be at least ONE or else really give up)
  //avoid giving up with page content type
  if ($default_type == 'page' && count($types) > 1) {
    $default_type = $types[1]->type;
  }
  foreach($types as $type) {
    if ($type->type == 'wiki') {
      $default_type = $type->type;
      break;
    } elseif($type->type == 'story') {
      $default_type = $type->type;
    } elseif($default_type != 'story') {
      if ($type->type == 'blog') {
        $default_type = $type->type;
      }
    }
  }
  return $default_type;  
}