afconvert --file WAVE --data LEI16 mysong.m4a

I can't get even a simple Calculator to run from within my sketch.  I'm getting a error=13, Permission denied.  I assume it is a security thing and the operating system is protecting itself from attack.  I read something about signing an applet.  Would this apply to what I'm trying to do?  If so I assume I can't sign it until I'm done and created the applet.  How would you test it?

2.         // afconvert --file WAVE --data LEI16 Havona.m4a
3.         //String[] args = {"path/to/the.app", "--args", "arg1", "arg2"..."argN"};
4.         //String[] args = {"/Applications/Utilities/Terminal.app", "--args", "afconvert", "--file", "WAVE", "--data", "LEI16", "/documents/Havona.m4a"};
5.         String[] args = {"/Applications/Calculator.app"}; // error=13, Permission denied
6.         exec(args);