A flood protection should have been implemented. You don't want people to flood you with all those "insults," Do you?

Plus the > /set %Insult $rand(1,100) can be changed to

var %insult = $rand(1,100)

so you don't have to waste a space in your variables. If you insist on using the /set command, at least add a -e switch > /set -e %Insult $rand(1,100) to get it unset when mirc exits.