Hi Zuki,
unzip file.
When you open the file in song book software,
you bring up the main folder "Songbook.set"
NOT the "songbook" folder inside ..

Basically
when you get the Browse for Folder Pop Up
(at the top it says "Select a ".set" folder to read from")

at the bottom where it says
Folder: ( you choose) songbook.set


Hope I'm making sense.

If still not working maybe the file got corrupted when I zipped it.

best wishes
rikki