CSS: An invalid XML character (Unicode: 0xa0) was found

Please note that I am not a part of the mailing list, so if you could 
please respond directly to my email (or CC me), I'd appreciate it.

I'm working on a test site for an ISP, and for some reason, the CSS 
validator comes up with a wierd error.

The site:
http://testing.worldwithoutwire.com/

CSS Validaton link:
http://jigsaw.w3.org/css- 
validator/validator?uri=http%3A%2F%2Ftesting.worldwithoutwire.com%2F&warning=1&profile=css2

The error:
Please, validate your XML document first!
Line 116
Column 22
An invalid XML character (Unicode: 0xa0) was found in the element content 
of the document.

But, I already sent it through the HTML validator, and it came out as clean 
XHTML Transitional.  The line it points to has just a single </div> tag, so 
I'm a little confused.

-- 
sasha