Because you're manually setting the widths of tables and columns to numbers that are too large:
<table width="800" border="0" cellspacing="1" cellpadding="0">
<tr>
<td class="tablebgcolor">
<table width="798" border="0" cellspacing="1" cellpadding="0">
<tr>
<td class="navbar" height="23">
<table width="796" border="0" cellspacing="0" cellpadding="0">
If you want the table and cells to fit the content, do NOT set the width="" attribute