Okay, I haven't really seen the theme's code before so I am not sure how well this will work.
Try opening footer.php. It looks like this:
</div>
<!-- main END -->
<?php get_sidebar(); ?>
<div class="fixed"></div>
</div>
<!-- content END -->
<?php include('templates/end.php'); ?>
So the deal is that the footer is called by (almost*) every other file in the template, so the sidebar will always load. So replace that line (the fourth one in this particular file) with:
<?php //get_sidebar(); ?>
And this should very likely work.
Good luck :)
*There's a page-without-sidebar.php (or something to that effect) that does not call the footer at all.