This looks like the same outcome as was posted under: Re: New Zonealarm update is crashing outlook on 16 April last year.
Happens on Outlook and Outlook express. Was running a v6 ZA s'suite (v7 buggy)an auto update came through, now I can receive messages, view old messages,some new messages but cant send emails. I have tried re-installing both outlook and express, I have uninstalled ZA (no luck), installed V7, no change
Not a memory problem - I have 24GB available, deleted old messages - hasnt helped open to suggestions
Operating System:Windows XP Pro
Product Name:ZoneAlarm Internet Security Suite