Works like a charm.
Previous comment, RTFM
"Important: You must first select the files in the list you want copied (see below)-then press "backup", otherwise you will get an empty backup folder! To copy files, they must have permission for read/write. This can be an issue with system files, preferences etc. The destination disk also must have read/write permission and be Mac OS extended format. Some other disk formats will not work with this kind of script. You can change permissions globally, in the Accounts pane in System preferences, if you are the administrator on your computer, or you can change individual file permissions by control clicking "get info" for individual files."