This page places AdSense ads to 404 error page. Isn't that a TOS violation? Or it's not a rule any more? http://error.hosted.filefront.com/404
Are 404 pages explicitly not allowed in the TOS? I would think the "no content" part of the TOS would make this a violation.
Yes you are allowed to have google adsense on error pages. The TOS for google is outdated and they still haven't updated it. Peace,