@JohnK The example attached works for me. Really, you only need to lowercase the filename, not necessarily the reference to that filename.
@Erel The problem of exporting as zip is that it doesn't include the files under Files that are not added to the Files tab. So it's not so useful when you are using subfolders under Files.
I now this is an old post, but I have similar problem.
I test joseluis project, and after correction of directory name it works fine, so ReadMap work.
But if i use File.Exists :