Installed ZASS v9.1 on top of ZASS v8.0.400.20 and ForceField (standalone) v22.214.171.124 .I untick to Load ZA at startup and rebooted.Install over the top.Untick keep my current ZoneAlarm settings.Only option offer was Upgrade Now.Looks like running with out issues so far.
It also uninstalled ForceField (standalone).I loaded Firefox and IE8 and both had the limited ForceField toolbar installed.I install ForceField (standalone) and every thing resolved.Full functional ForceField.No issues.
Scan Schedule and Update anti-virus works.I only tried one hour.Manual update works.They add option for Rootkit Scan.
No issue with Windows Security Center.Overall looks very stable so far.Will followup if any problems occur.
XP SP3 (all updates)
ForceField (standalone) v 126.96.36.199
ZoneAlarm Security Suite version:9.1.008.000
Anti-virus engine version:188.8.131.52
Anti-virus signature DAT file version:995318432