background-color 'transparent' not right valid with any color?

Hi all,

it seems to be a problem to use background-color as 'transparent' while setting the color to any value.
The CSS Validator validates the whole CSS definition but still gives a warning that no bgcolor is set.

<style ...><!--
body { background: #ffffff url(/bg-main.jpg) no-repeat fixed 50% 50%;}
td { background-color: transparent; color: blue;}
--></style>

To show you what I mean, I created a test page:
<http://dark-chiaki.net/w3c/style/style-error-032.php>
Just click the CSS-image to get the page validated.

Anyone who can help?

Best regards,
Chiaki.