Writing data to Program Files is an outdated and insecure method. You would have to force the user to give your application admin rights - which is crazy.
I suggest having a read: http://www.rajapet.com/2013/12/its-2013-stop-trying-to-write-to-the-program-files-folder-already.html
To be specific: My app doesn't modify the content, just reads it. Only the installer writes to it. And it's not per-user. Should I install to File::commonApplicationDataDirectory?