I don't know if this will change it but when I look at your source code... in one table is a closing td tag missing
------code start------
<table style="BACKGROUND: #ffffff; width=800px;">
<tr>
<td>
</tr>
</table>
-----------code end -------
some like that can mess up pretty badly.
It's in line 685 but that can be different depending on the customer testimonials content.
It is right above the <!-- central space --> comment. You might check that out
Don't know if it helps, Andy