I'm having problems with google feeds too.
"The previous page is sending you to an invalid url.
If you do not want to visit that page, you can return to the previous page."My other feeds work ok.
I did find this on Drupal forums
"Yes. The equal signs (=) are transformed into something else so the URL is no longer valid. This is also true on content aggregated from Google News.
Since many people will want to aggregate from google I do think it is a concern"http://drupal.org/node/611972Any suggestions on a fix?