I *think* that your problems are inside your layout table in tpl_main_page.php:
1. For the bar under the header area, before you draw the left column, you have inserted a DIV inside a TR, and not closed the TR before opening another one:
HTML Code:
<tr>
<div id="bodytop"><img src="includes/templates/newagecare/images/body_top.gif" width="553" height="84" /></a></div>
<tr>
2. Before drawing the right column, you have more mismatched table elements:
HTML Code:
</td>
<div id="imagemap"><img src="includes/templates/newagecare/images/alpha_map2.gif" width="194" height="206" /></a></div>
You likely don't want to put DIV's directly into TR's ... make TD's for them in order to be more compliant.
Also, don't put DIV's between TD's ... put them INside TD's.