As it states, it is "not-a-virus". ZoneAlarm and other AV programs treat mIRC as a potentially dangerous program and warn you if you have it on your computer. You can disable this in most of those AV programs by either setting the programs to not warn you about those types of things or tells the prorgams to just ignore mIRC and tell you about any other similar programs.
Basically, if you purposely installed mIRC and you did so from a download from this site, you don't have anything to worry about. If you didn't install it and it just suddenly appeared on your computer, it could be that a virus that is set up to use mIRC got onto your computer. That's really all those warnings mean.
