Why W3C CSS Validator showing parsing error on "Ends-with" Attribute Value Selector

Why W3C Validator showing parsing error on this. I selected CSS3 profile also from dropdown.

a[href $=.xls]{background: transparent url(ms-excel-icon.gif) left top no-repeat;
padding-left: 22px;display: block;h开发者_JAVA百科eight: 16px;}

alt text http://shup.com/Shup/347107/11042455758-My-Desktop.png

They have a nearly identical example up on the W3C site

a[href$=".html"]

with the only difference being that there's no white space between the attribute name and the constraint type and the constraint itself is in quotes.