How Do I Get Rid of Those Pop-up Ads?

First things first... I noticed a few days ago that opening Spinning Lovely Days garnered me a message from my pop-up blocker that it had just blocked a pop-up. I mean, from my own blog. How did that happen? I then remembered receiving a message from Bidvertiser saying that they were enabling pop-under ads, which supposedly were much less intrusive than regular pop-ups. Anyway, certain that that was the culprit, I disabled the pop-under ad option in my account. Imagine my dismay when I realized this morning that the pop-ups are still there. I think the last widget I added was the carbon neutral one, but I don't think it's causing the pop-ups. Let me know if you can figure this out; I'd appreciate any advice regarding this.