It would be preferred for very obvious reasons that you don't go pasting URLs which might be infected with viruses. Users without antiviruses are just as likely to click on them at these Forums than they are whilst on IRC.
If any official patches are released for mIRC, then they will be posted ONLY on this website. Seeing as only one patch has been released in the past, and that was for special reasons and it was years ago when mIRC wasn't as popular, future patches are not going to be released.
Anything which ends in .exe and is advertised to you privately by someone you do not know is very likely to be a virus, it's a popular file extension for them (but by no means the ONLY extension).
I tried the URL on IE 6 and it didn't work.