[www-validator-css] <none>

I was hoping you could help me clear up a problem I'm having validating a
URL.  The W3C Markup Validation Service passes the markup as valid Xhtml
transitional, but when I use the W3C CSS Validation service it reports that
I should validate the XML document first.

The CSS report say that:

Element type "img" must be followed by either attribute specifications, ">" 
or "/>".

Which makes no sense to me because the img element in question IS followed 
both by attributes AND "/>".  Also, the img tag is virtually identical to 
other tags which HAVE been passed.

This leads me to deduce that there could be a bug somewhere, as there is a
conflict of "opinion."

Can you help?