What is 68.87.73.242 & why is it trying to get in?

This is regarding a Zone Alarm alert. I've also posted at ZA forums.

A ZA alert window comes up saying 68.87.73.242 has been blocked. I click ok and within seconds it reappears. I left it open and the alerts steadily total up (333 and counting).
My ISP is Comcast and I'm running WIN98SE. I have two other computers, one also WIN98SE and the other WINXP. Neither of these seem to be getting this alert even though they have ZA.
We're on a router and the computer with the alert problem is I guess the "main" computer.
I searched for 68.87.73.242 and didn't understand any of the many results. It seemed that this number is possibly associated with Comcast, but I'm not sure.
Should I allow it access?
If so, how do I do it.
I'm totally clueless re: computer-ese, tweaking, etc.
Thanks ahead!

 

Wow...that's some service.
One minute after posting, another similar post and the answer I needed.
You guys are the best!
OooRah