Two particular email addresses keep going to the Zonealarm Junk Mail folder

One was solved by adding the email address to the Allowed people list, the other, who is an important client, has been "UnJunked" everytime it enters the Junk mail folder but the next email sent by this user still goes straight to Zonealarm Junk mail.
The persons email address is already in the "Allowed" people list and their domain name is in the "Allowed" Companies list.

Software versions are -
Zonealarm Internet Security Suite version is 8.0.298.035.
The OS is Windows XP Prof SP3
Email Client is Outlook 2003

There are no other Antivirus, AntiSpyware or Firewall programs running on the PC

Before I do a complete clean uninstall I wanted to check if anyone had any other ideas.

Just a quick observation - I wonder when moving from version 6.5 to version 7.0 back in 2007 if a clean uninstall/install rather than an upgrade was performed would a lot of these problems have been avoided (Now and again I still get a virus alert for RealVNC)
Remember it was in Version 7 that ZoneAlarm moved from the Computer Associates antivirus scanning engine to the Kaspersky antivirus scanning engine - maybe there is still some CA files remaining causing conflicts.

Operating System:Windows XP Pro
Software Version:8.0
Product Name:ZoneAlarm Internet Security Suite