so now i finally see what you're calling a whisper.
a WHOIS is a message sent to the server to get the ip address and 'name' of a user. The person you do a /whois on - does not see the results of this, nor does not even know you're doing a /whois on them. The exception is that a small handful of server admins running the irc server are able to see when someone does a /whois on them.
Normally, the reply to "/whois nick" appears in status window, with the exception that if mirc-options/irc/show-in-active has a checkmark next to "whois", then the reply would show in your active channel.
As for your problem with notice being an invalid command, I noticed your answer showed you didn't paste my example, because my example used "test", but your answer used "hello" instead. Can you see if you still get the unknown command error if you use notice like this:
