Mike,
apparently there is another device that uses port 88.
You have two options:
a) find that one and assign another port for this device if powssible or
b) assign another port to your webserver.... (seems the easier option)
and yes, c) replace ZoneAlarm with something else, like Comodo Personal Firewall (
http://www.personalfirewall.comodo.com/)
I have half a dozend webserver running on one machine, and all are accessible from the internet, using those dynamic DNS-services like that NO-IP you mentioned. It was quite easy to setup all of them, so I know it has to work for you also!
bye
Wolfgang