Problem: Disabling comments causes right sidebar to start below left content section and to lose formatting
Cause: comments-nice-bg and comments-nice divs are repeated cause the close tags to be in the wrong spot

Resolution:

Firstly make sure that your wp-content/themes directory is writeable by your webserver
chown apache:apache path/to/themes -Rv

Next. In wordpress admin console open Presentation => Theme Editor ==> Comments (located in right side bar under 'Sumanasa Design02' theme files)

Find the following section and comment out the two offending divs

<?php else : // comments are closed ?>
<!-- If comments are closed. -->

<!-- removed by james so that the search bar wasn't at bottom of page
<div class="comments-nice-bg">
<div class="comments-nice">
-->
<div class="postinput">

<p class="nocomments">Comments are closed.</p>

<?php endif; ?>

Note: You can edit the file on the hard disk by going to /path/to/wordpress/wp-content/themes/sumanasa-design02-10/ and opening comments.php