I have first noticed this sometime around Sunday, 25^th of August, 13:00 GMT

Looking at the HTML source you can see that Error: appears instead of the <IFRAME> or <LAYER> tags (depending on your browser), so the problem is not with Perlmonks themselves but rather with the advertising server at http://adfu.blockstackers.com/servfu.pl?l,perlmonks. While surely this might be seen as an "improvement" because you don't see advertisements, but I wonder how this would affect Perlmonks advertising revenue (they are getting payed for this, right?). Reflecting on this I believe it might be of interest to the community to get this thing fixed ASAP in order not to suffer any revenue loss.

Just my thoughts.

Oh, I am an economics student so things like revenues are usually on my mind ;)