I did a search and didn't see anything about this issue.
First of all, my versions:
ZoneAlarm Extreme Security version:9.1.008.000
Anti-virus engine version:22.214.171.124
Anti-virus signature DAT file version:997145440
ZoneAlarm ForceField 126.96.36.199
ZoneAlarm ForceField Spyware Scanner 188.8.131.52
ZoneAlarm ForceField Anti-Phishing Database 184.108.40.206
ZoneAlarm ForceField Spyware Sites Database 04.005
PC O/S: Vista Home Premium 64bit
I was digging around in ZA and I found under advanced settings the "Enable virtualization" checkbox, saw at the top of the form that shows "Normally there is no need to change these settings" and wondered, if virtualization is such a powerful piece of the software why it wasn't checked by default. I checked it and it needed to reboot the browser (I think I remember this right) - anyway I could no longer open IE8, tried rebooting the pc and still couldn't open IE8. I found the checkbox under forcefield settings and unchecked it again - now IE8 came right up.
Anyone else seen this issue?