Hi, not having used zonealarm for 2 years or so due to switching to Linux I am a little rusty on it, but on looking at the website I see trial versions only last 15 days. So I cant see why folks want to use something that lasts for 15 days. If it is because you want to see how good it is and want to use mirc then contact zonelabs and ask them. OR pay the 40 bux and register/upgrade to the full version.As I do know that version does have the block/unblock irc option.
Just my few cents

Good luck

Happy mIRC user on Linux