In Google webmaster tools I have around 46k URL's that are not being followed by Google. The only thing that they all have in common are special characters in the URL. Here's an example:

http://cellphoneforums.net/fr/general-service-provider-forum/t348277-ting-code-promotionnel-rabais-de-50-$-sur-n-importe-quel-t%C3%A9l%C3%A9phone.html

notice how the special characters change - Google doesn't seem to like this