No. ID's are for single unique elements. If you want to specify an ID to style many elements you should be using the 'class' attribute - exactly like what you've done for your website (I cant see any duplicate ID's but I can see duplicate classes).
For example this would be acceptable - however it is odd to assign the same class name to different tags. I think you would typically want same classes to both be either <td> or <div>, one or the other but not both. I don't think there's anything saying it's not allowed but it will make things easier to code & understand.
HTML Code:
<table>
<tr>
<td class="btmnav">
<a href="http://amzn.to/VNNoXQ" target="_blank">Click here to see the best deals in Water Ionizers at Amazon</a>
</td>
</tr>
</table>
<div class="btmnav"><?php include("$rpath/1cde/btmnav.php"); ?></div>
Reading this should help explain it a bit better than i can:
http://css-tricks.com/the-difference...-id-and-class/
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