As I wrote at first: My code works on Windows fine because both strings (in JS and get filename) is encoded as UTF (Normal Form Composed) eg.: „č“ is one UTF8 character (2 bytes).
On Mac you get filename in UTF Normal Form Decomposed is „č“ as c + ˇ (accent).
Yes, basic problem is in really old-fashioned file system HFS+.
But Mac OS X API has since 2003 methods for convert Decomposed to Composed form a vice versa: http://developer.apple.com/library/mac/qa/qa1235/_index.html
So why Adobe can't use it in their SW, I don't understand 
It is the similar problem as Adobe CS you cannot install on case-sensitive filesystem (new feature in Mac OS X 10.4 
).
I'm sorry, I'm a little bit angry because I spend hours of debuging this stupid problem.
Over all thank you for your time and patience.