ZoneAlarm updates are comparatively infrequent and it's best to set for Manual updating - there's always at least one thread on the forums advising one is available.
You don't need to reinstall ZA. Just install over the old version (upgrade rather than clean install) and click Yes when asked about the type of installation. Your configuration will then be retained, except you will have to choose Manual rather than Automatic updates as the latter is the default.
In any case if you don't update immediately a new version comes out there's nothing to worry about.