Calendar shows at botton in IE

I am using the dxx theme, colour scheme modified, and have added the calendar function. Everything works fine in FireFox, but in IE everything below the calendar is placed at the bottom of the page – http://www.teejayuu.co.uk. The code around the calandar call is:
<?php wp_list_pages('title_li=<h2>' . __('Pages') . '</h2>' ); ?>

<li><h2><?php _e('Archives'); ?></h2>
<br><?php get_calendar(3); ?>

<ul>
<?php wp_get_archives('type=monthly'); ?>
</ul>
</li>
<li><h2><?php _e('Categories'); ?></h2>
</li>

Any help is appreciated.
Also any comments on theme or content also appreciated