Hi, I am working with Google support on this issue, but I figured I might check to see if any other dream hosters might have encountered the same issue.
I run a wordpress blog at http://www.toronto-sushi.com/ and have used various plugins to display google ads.
Some time in the past few months, something went kablooie and the ad code returns an error 400.
The ad code, whether implimented by a wordpress plugin or through
straight html results in this:
Which returns a 400 in IE, and nothing at all in Firefox.
So far the only suggestion they've had is to blame a non-existant robots.txt file, but to be safe I followed their advice and created one that basically said google can go nuts and do whatever.