Did you use midi files from vgmusic.com as your base?
I think so, I work with midis that I made or from around the internet (when I can't do the chord that I want, so I hear over and check if it's the right one). I don't remember if I did used some songs from there.
Anyways, when I work with midi files, I always check the original at the same time, because sometimes the midi files have some timing problems or chords or notes that aren't right.
