I finally got this mod to pass the XHTML Validator. A couple of tricks, but it passed.....
All the javascript in the sidebarext_temp needs the cdata tag to hide it from the validator. This is a band-aid.
Code:
<script type="text/javascript">
//<![CDATA[
java scripts here
//]]>
</script>
And the embedded css was moved out of the sidebarext_temp to the additional.css file.