My system was a little more informative: it appears your virus checker is blocking Java 6 from going out to the internet and downloading an update. The problem is the file that it is trying to download is called sex.avi and it happens while using Internet Explorer.
I just switched over to Safari and the popup blocker doesn't happen, which is kind of unusual as some MAC users are getting the same issue(I am assuming MAC users are using Safari).
I have my virus checker block just about everything and to alert me when any program tries to go out to the Internet and Java is one of those programs I have blocked. When it happens, Java puts a small icon in my status area and only has a few options: goto java website, updates and hide icon, there was no close/quit/exit option.
So, for those not having the issue, perhaps their virus checker allows Java to go out and perform auto updates, like Windows. Right now I have the dumb Macrovision application constantly trying to go out and get updates, this is Blackberry's desktop application that I loaded to pull pictures and videos and thought I might load mp3 onto my blackberry, used it once and have never put any music on my blackberry.