Few people which correctly added their Publisher ID reported then in place where banner should be displayed, they get 404 Not Found error. My banner is displaying ok, but their doesn't work.
Is it maybe because you can't show other pub-id on your ad_slot?
Also, I've put "1" in "ShowEveryXPages" to display banner 50/50 but it's not working. My banner is displayed 3 or 4 times and then banner of thread starter.