Print the comment form with PHP
comment_form() is expecting the parameter to be an object rather than an array so you should be doing something like this:

$comment = new stdClass;
$comment-&gt;nid = $row-&gt;nid;
$form = drupal_get_form('comment_form', $comment);


Note the lack of a 3rd parameter passed to drupal_get_form(), comment_form() only accepts the comment as a parameter, if you want to add a title you'll have to print that separately.

Finally drupal_get_form() returns a render array rather than a string so you need to pass it through the render() function:

print render($form);


The extra errors you're getting are just side-effects of passing an array rather than an object to the comment_form() function.