It is an annoying message.  The directory must be hidden...I deleted just about everything and ran the mcLuaEditor.exe from a memory stick and still had the same problem...just on that computer.
I ran the mcLuaEditor.exe on another computer and it ran just fine.

I may have found something while at lunch today....

../AppData/.../wxLuaIDE.ini

I will look for that same .ini file when I get home.

 
Fixed It!!!!!
 

I corrupted the wxLuaIDE.ini file; probably while editing a script then crashing Mach4 and killing the process.  ...I am sure nobody has ever done that here 

Running Windows 8.1 64-bit
I tried to change the value on an older machine to recreate the suspected problem but Lua automatically fixed the problem; but it did not fix it here on this machine.

The following is a snapshot of the location and the file you need to edit.... In my case, change from the MatchCase=4 to MatchCase=1 or =0...this is part of the Find Function.  (The error message was telling us what the problem was.  It just didn't tell us where the file was).  Note:  This file is written every time you close a LuaEditor window.

Holy sh!tB@lls batman!! That is freakin awesome! ?Good looking out Tim. Thanx for letting us know if we ever encounter that issue!

--josh

by the way, I just changed my name from 20,000 Axes to just my first name....just so your are like "who the heck is this guy?"

Yep... when I saw your first name I thought it was 20,000 Ex's.... I have one or two of those