Do you have a midi device (translator) connected to keyboard/sound module, they could be at fault.
My relatively new Yamaha keyboard has never missed a note, but when I attached my Grandfathers older keyboard recently (made by GEM) it skipped notes frequently.
It was very annoying cos some of the sounds were much better, and it had reverb effects and stuff.
So test it with other midi instruments, that's all I can think of...
