Printing individual components of comment-form in comment-wrapper.tpl
You forgot to render hidden form fields that are required for the correct work.

Just add this line of code after outputting all visible form fields:

&lt;?php 
  print drupal_render_children($form); 
?&gt;


Also if you output form elements outside form template you need manually add {form} tag
In your case you will get

&lt;form id="comment-form" class="comment-form" accept-charset="UTF-8" method="post" action="&lt;?php print url('node/' . $node-&gt;nid); ?&gt;#comments"&gt;
&lt;?php
  print render($content['comment_form']['author']);  
  print render($content['comment_form']['field_email']);
  print render($content['comment_form']['comment_body']);
  print render($content['comment_form']['actions']['submit']);
  print render($content['comment_form']['actions']['preview']);
  print drupal_render_children($content['comment_form']); 
?&gt;
&lt;/form&gt;