Hello Oz,
It will not work if you simply scan the sheet music - it needs to be a proper PDF file - as it says on their Web site :-)
Why don't you try to find a MIDI version of the song first and then import it to a notation programme like Sibelius or similar - you would get much better results that way. Or edit the MIDI file on your keyboard - depending on what you want to do with it.
Cheers, Roland