It sounds like you need to add a few lines to your header.php and footer.php creating a separate table in which to "house" your board. That provides the initial table with the blue background and then a 95% table with the actual board content. The lines you'd need to add are:
In
header.php:
<br>
<table width="95%" align="center" cellpadding="0" cellspacing="0" border="0">
<tr>
<td align="center" class="menubar"><br>
And in
footer.php:
<br></td></tr></table><br>
That should give you the look you're looking for.
P.S. A link would
really be helpful in helping you figure out what's going on.