Sound quality on piano tracks

[EmpireJones 0]

I have been trying to record MIDI piano tracks. When I try playing the tracks back, what usually happens is that everything becomes sustained, as if I was playing with the sustain pedal down the whole time. Other times the sustain is cut out completely. The same things will happen when I try converting the tracks to mp3 files. Anything I can do about this- is there an effect that needs to be turned off or something?