I'm on a highly secured military network. While it's not impossible that there's malware on my computer, I think it's more likely that something's up with the website.
Edit: There's no choice of browsers on this network. It's IE 7 or nothing.
If you're browsing random sites that could well be infected, even if you weren't using IE7 the fact that you're on a "secure military network" doesn't stop you from being just as vulnerable as anyone else browsing random sites. Sounds to be like the security of your network has at least one hole in it.
The "secure" US networks are also just full of malware, because at the end of the day you have a bunch of random enlisted men clicking around in IE 7. I've heard plenty of accounts of the malware on these things.
Edit: Screenshot - http://i.imgur.com/5lnJ7.jpg