I assume you have access to the gzline command?
You have the web site with spaces in it... that may just be for your example, but if not, that could be the problem. Also, I'd suggest putting a * in front of the trigger text as well... *www.mirc.com* so it catches it anywhere in the text, rather than just at the beginning of the line. It will also allow it to catch
http://www.mirc.com/ by doing that.
Just as one other note... you have an extra } at the end. It won't hurt having it there, but it's not needed.
