Midi/Piano Roll is not triggering all notes.

Ok so....first post on here let me know if I'm in the wrong area but..I had opened Session Drummer 3.  I am not using a midi keyboard at this time, I'm just manually adding midi in thru the piano roll.  It works perfectly fine when I playback like once, BUT after a while at no particular out of the ordinary time, session drummer does not to trigger all the midi notes.  Its also not the same trigger every time its just scattered in a different place every playback.  This was not a problem when I first purchased the product about 4 months ago.  Also if I mix the project down to a WAV, mp3 etc it plays all the damn midi notes.  Very confused.  Also to add I've had quite a few projects with A LOT more going on and never had this problem.  My computer usage is extremely low as well, I checked to see if I was overloading anything.  Just like to add to this now that it is ALL my midi data not working anymore.  It all just stopped...help? damn.

-Sonarx1 Producer
-8 gig-o-ram
-windows 7