You're obviously using mIRC purely as a file trading program, probably because a friend told you it's good for that purpose. mIRC is a chat client, you do not use it for mass/illegal file trading.
CTCP Ping/Time/Version/Etc. are the default CTCP messages, however, scripts can be set up to trigger on other CTCP events (i.e. in file servers) which is what file serving scripts sometimes do. This is what you're thinking of it seems.
If you're trying to get mp3s/movies/software then that is illegal due to copyright infringement aswell as a good way to get viruses. For more reasons see
this post.
Regards,
