When I type /sumi in mIRC, I get “Unknown command: SUMI”, why?
For some reason, the SUMI installer didn’t add the /sumi command to your aliases.ini. Its supposed to do this automatically, but sometimes things don’t work correctly with mIRC add-ons or strange configurations. You’ll have to do it manually: read client-side/mirc.txt and add it to your aliases.ini (Alt-R, then go to the “Aliases” tab). /sumi commands should now be recognized.