akai s950 stops receiving midi..

My s950 is acting weird... if I send it midi note 40 it plays a few miliseconds of the sample and then goes quiet, and now won't play anything at all. The midi receive light doesn't blink even though I send more midi to it. If I press the Midi button (and maybe others) it'll start receiving and playing samples again, until the next time note 40 arrives...

Any ideas?

it has something to do with the program, since I created a new one and loaded the samples and its working fine. I had copied the previous program and created several variations, all which were defective, which made me think it was something up with the system. still no idea what caused the issue in the first place though