Unzip the file and check for errors, In the extract.js line 51. So that 'existed' has always been false.

var names = $.map(fm.files(hashes), function(file) { return file.name; }); //line 51
...
existed = ($.inArray(name, names) >= 0), //line 105

The names should be the collection of all sibling elements of the selected file.
The 'fm.files()' accept parameter should be The 'phash' of The selected file, not The 'hash' of The selected file.