Strange CSS-Error

Whenever i check the CSS on my site with the CSS-Validator i get the following error message:

“URI : http://TLD/wordpress/print.css

* Zeile: -1

Datei nicht gefunden http://TLD/wordpress/print.css: Not Found”

I looked up in my WP directory, but there is no print.css…

Can someone help me, what is wrong here? I used the Validator on some other WP-Blogs, but none of them showed that error…