Disklavier

I have a few PianoDisc Cd's that I bought on Ebay. Can anyone tell me why  
some of them will play on a Yamaha Disklavier and some will not.
I know this is a Disklavier users group but we share the same  interests and 
some products are interchangeable so I thought someone may  know the 
difference in these disks.
CD # 12013 and CD 2009 play the piano part and accompaniment fine but CD  
12011 and CD 12012 play the accompaniment but the there is a fax like tone  
instead of a piano part.
PianoDisc has a lot of nice music but I can't figure out which CD's will  
work and  which will not.
Any help would be appreciated.