I'm trying to print a comment form with 

    <?php 
        print drupal_get_form('comment_form', array('nid' => $row->nid), t('Post new comment')); 
    ?>

But all I get is 40 repetitions of 

> Warning: Attempt to assign property of non-object in comment_form() (line 1845 of /home/admin/public_html/website.com/modules/comment/comment.module).`

The comment form is called from inside a [PHP Views][1] field. What is the proper way to add a comment for to a node in Drupal 7?

There's actually a lot more errors, most of which repeat at least once:

> EntityMalformedException: Missing bundle property on entity of type comment. in entity_extract_ids() (line 7501 of /home/admin/public_html/website.com/includes/common.inc).
> Notice: Trying to get property of non-object in comment_form() (line 1854 of /home/admin/public_html/website.com/modules/comment/comment.module).




  [1]: http://drupal.org/project/views_php