Insert-songs not working

[sep2345]

Anyone have an idea why I'm only getting "blank" songs inserted into my library after running the "insert-songs.py" script? The correct number of songs is inserted but every song has a blank artist & title.
Everything goes smoothly with Exportify creating a nice csv of my playlist, then "retrieve-identifiers.py" seems to create a nice file of matched identifiers.
As a test, I created a simple Playlist of Katy Perry's Prism album (Deluxe version - 16 tracks). 16 identifiers show up in the "spotify.csv" file and after running "retrieve-identifiers.py", I have 16 identifiers in the "itunes.csv" file. I then run the "insert-songs.py" script and end up with 16 blank songs... Not sure what is happening. The only difference I see compared to Simon's instructions is that the Headers came from ID-7 not ID-4 (as viewed from within Charles).
Any ideas?
Thanks,
Scott