I didn't work on the install of this application, I only needed to figure out how to silently uninstall it to make way for our new firewall that was going to replace this. This was a huge pain, but I finally got it to work. Here is how I did it.
1) Disable the TrueVector Internet Monitor service using psservice, which is part of pstools with the command:
psservice setconfig "TrueVector Internet Monitor" disabled
2) Removed the startup entry from the registry for iclient.exe. To do this I added the following to a file called RemStartup.reg:
Windows Registry Editor Version 5.00
"Zone Labs Client"=-
Then I executed the following command to merge the settings into the registry:
regedit.exe /s RemStartup.reg
3) Reboot so that the service is stopped and iclient.exe is not running anymore
4) Execute the following command to uninstall the software:
"C:\Program Files\Zone Labs\Integrity Client\zauninst.exe" /s "C:\Program Files\Zone Labs\Integrity Client\INSTALL.log"
5) Now here is the tricky part, after the uninstall completes, you are left with a dialog box saying press OK to reboot. So I created a WiseScript to check for the presence of C:\Program Files\Zone Labs\Integrity Client\iclient.exe every 10 seconds, the script exits when it doesn't find it, so you know that is when you are presented with the dialog box. All you need to do is reboot the pc via your favorite method at that point(shutdown.exe /r for example) and you're all set.
Of course you can use vbscript or something to do this same thing, but wisescript was a quick 4 lines so that's why I chose it.