http://www.esl-blog.com/archives/000502.html has the ads and www.esl-blog.com has an updated ad_network.php but my site has stopped validating. It says no ads on http://www.esl-blog.com/archives/000502.html - Can anyone help me identify and fix the problem?
What's the location of your ad_network.php file? You may need to rebuild your MT blog after updating your ad_network.php file since MT generates static pages of content.