yeah I have been getting this problem with FF for a few days now. It just started in IE and I don't even have a pop up blocker /in/ IE. It also just started today in Opera.
No I don't have a third party pop up blocker on my system, but I do in FF.
Opera 8.51
IE 6.0.2800.1106.xpsp1.020828-1920
FF 1.5.0.6
I see the banner ads, but then it redirects to the page saying that I'm running an ad blocker... I'm not running one, only a pop up blocker but that is for good reason

I don't mind banner ads at all, but intrusive pop ups/pop unders make one not wish to visit the site again.