Don’t Update Zonealarm (Yet)
One of the problems the Bloke experienced was ZAP locked the volume, preventing the check disk utility from running at start-up. Others have reported that using the update check or trying to get more info on an intrusion attempt resulted in either hanging or a page stating there is an Apache server error. Some have also experienced problems with Norton Antivirus checking emails since installing ZAP version 5.
The solution to the problem was to uninstall version 5 and then revert to an earlier version (version 4.5.594 seems to be a good one).
It’s unfortunate that a company that has enjoyed such a good reputation appears to have slipped up big time. Blog Bloke recommends waiting for a Zone Labs to provide a more stable version before considering an update.