To the best of my knowledge, there has never been an mIRC version made specifically in another language. There has been a concerted effort to help non-English users for a long time now, but I think converting mIRC into another language completely would be too time consuming.
You can get help installing/setting up mIRC in Spanish
here and you might like to look at the
Translations page.
You may have used a script that was written in Spanish (i.e. it could have had custom dialogs etc) - I don't know a specific script that's like that, but you might try searching
Google.
Hope this helps
Regards,
