1 month ago:
Ok, we've done some testing (and even bought the virus protection app you guys are using so we could test it out). So far we haven't been able to replicate the error which leads us to believe the problem was a 3rd party ad which, hopefully, has been pulled.
That being said, we'd like to be vigilant about this. So if you see this problem again, can you:
1) grab the source code for the page where you see the error/warning. You can do this by going to the "view" menu in your browser and selecting "view source" (or something similar). Once the source appears you can copy and paste it into a text editor and save the file. Alternatively you can go to the file menu and select "save page as..." and save the html file to disk. This shouldn't download any virus or anything since all you're doing is saving the html wrapper for the page.
2) Take a screenshot of the page. If we can isolate whether or not this is a problem advertisement, we can contact the appropriate ad network and let them know there's some problem ad code.
3) pm me (and I'll tell you how to get me items 1 & 2.
Thank you!