I'm trying to open a specific port in the free version of ZoneAlarm 8.0.298. Only one program needs access to this port, if it makes a difference. I attempted to RTFM, but got stuck on Step 2 of 'Blocking and Unblocking': "In either the Trusted Zone or Internet Zone area, click Custom." I don't have a 'Custom' button anywhere in the Firewall tab. It's just not there. What's going on here? How can I move forward?

Operating System:Windows XP Pro
Software Version:8.0
Product Name:ZoneAlarm (Free)