You can rename the mirc.exe file to any name, as long as it begins with "mirc".
This is in an attempt to discourage people from tricking users into running it, sneaking onto people's machines unbenounced to them, or simply taking credit for the author's (Khaled's) work. The last of these is the most common, with people renaming "mirc.exe" to "mystupidscript.exe".
What can you name it?
What you can't name it.