Disklavier

I have a MX100 II and have been downloading and making floppy disks 
which play beautifully thanks to help from members of this site.  I 
recently purchased a USB to MIDI adapter and am able to connect the 
computer directly to the Disklavier and play the MIDI file from the 
PC.  It works great!  Until the end of the performance when the last 
notes or pedal motion freezes which cannot be good for the piano.  The 
same file plays fine when it is on the floppy but the last keys remain 
depressed at the end of a MIDI connected performance.  

Is there something that needs to be set on the Disklavier or do I have 
to edit each MIDI to end the tune?  Details, if you have them, would be 
appreciated.

Regards,

Mike