Disklavier

Does anyone know why the Mark III Disklavier will play the piano part 
on some PianoDisc CDs (www.pianodisc.com), but not others?

A few months ago I purchased six PianoDiscs, mostly live/orchestrated 
discs from the Artist series.  Five of them played fine, and only one 
wouldn't play the piano part.

A few days ago, I purchased six more PianoDiscs, again mostly 
live/orchestrated discs from the Artist series, but of the six, only 
one plays, the other five won't play.

On the discs that won't play, the piano just plays random notes that 
have nothing to do with the music.  Maybe they are some sort of 
control data?  I tried switching track 1 to be played by the internal 
synthesizer instead of acoustically on the piano, but it is still the 
same random, non-sensical notes being played.

Is there any solution to make these discs play?  A setting that can 
be changed, or some way of extracting and converting the piano music 
data?

I realize of course that these discs are not really intended for 
playback on the Yamaha pianos, but was just wondering if anyone had 
discovered the secrets to making them work.

Thanks in advance for any help.

  - Bob