After I installed IE9, I started getting the above message about every 30-45 minutes. I usually have more than one browser window open at a time, and the message relates to the one I'm using at the time. When I click "Close program", it closes the browser window I'm looking at but not the other ones that are open behind it. I uninstalled IE9 and went back to IE8 but I still have the problem. If I shut down ZoneAlarm, I never get the message and have no problems. I've tried uninstalling ZoneAlarm and re-installing it but that didn't help. I also uninstalled ForceField.
Windows 7 Professional 64bit w/service pack 1
IE Version 8.0.7601.17514
ZoneAlarm Free Firewall version: 10.1.079.000
vsmon version: 10.1.079.000
Driver version: 10.0.217.000
ZoneAlarm Browser Security: 1.5.350.0