Errors in Firefox

I am trying to code my WordPress template, and it has gone great so far. But now I have these weird stretching errors in Firefox. I am very experienced with CSS and XHTML but I can’t figure out what is wrong.

https://inject3.com/360blog/

Look for yourself.

Here is a link to the style sheet:
https://inject3.com/360blog/wp-content/themes/stealth-gray-mix-red-15/style.css

And the area where the Update Posts are (the place with the errors) is :

<div id="contentandside">

<div id="contentarea">
<?php if (have_posts()) : while (have_posts()) : the_post(); ?>
<div class="postcontain">

<div class="titlebar"><a>" rel="bookmark" title="Permanent Link to <?php the_title(); ?>"><?php the_title(); ?></a></div>
<div class="toppost"></div>
<div class="postcontent"><?php the_content('Read More'); ?></div>
<div class="postbottom"></div>
<div class="bottombarleft"> <?php the_time('M d, Y') ?> - <?php comments_popup_link('Comments? None yet', '1 Comment so far', '% Comments and counting'); ?></div>
<div class="digarea"></div>

<div id="clear"></div>
</div>

<?php endwhile; else: ?>
<?php endif; ?>

</div>

Any ideas?