Number of issues – Blog body box gone, YARRP error, thumbnail photo,timestamp,

There are a number of issues with the blog side of the theme. If you know how to resolve any of them would be much appreciated:

1. The white body box of the post page, in posts and on regular pages is not there (http://chloehodder.com/sequential-self-evolution/)
Demo of how it should look: http://www.templateaccess.com/wpdemos/wp203/?p=48

2. Sidebar is not showing when in a post

3. YARPP error at the bottom of posts – Fatal error: Call to undefined function yarpp_sql() in /home/chodder/public_html/wp-content/themes/heritage/heritage/single.php on line 78(YARPP is activated)

4. Comments not showing up

5. Unable to turn timestamp off (Activated the plugin Date Exlcusion SEO but that doesn’t change anything)
Single.php:
<!–/post-img –>
<div class=”post-date”>On (When I type Off, nothing changes)
<?php the_time(‘m.d.y’); ?>
 |  In
<?php the_category(‘, ‘) ?>
 |  by
<?php the_author_posts_link(); ?>
</div>

6. Random short white line horizontal when in posts and pages

7. How to activate the wide ‘thumbnail’ photo for posts specific to the theme I am using: http://www.templatesold.com/p_details.php?id=6028

Thanks