When I run your code I get the following error:
Error using copyfile
Cannot copy or move a file or directory onto itself.
Error in coupling (line 13)
copyfile(fullfile(path,file))
Therefore all you have to do is put your .m file into a different directory (folder) and that will fix your problem. E.g:
--- \Desktop
--- FAR.DATA
--- ECL1.INC
--- \Script
--- coupling.m
