How Do I Externally Sequence an MPC?

I've been trying to get this going for a little bit now and I just cannot get this figured out so I must ask ye gentlemen for a wee bit o' help....

Long story short:
I'm trying to sequence my MPC 1K (w/ JJOS1) from my computer using a lil' program. I set up my drum program on the MPC and then get my MIDI-USB cable connected, and set everything up to sequence the kick drum. All works. Now - when I try to sequence another sound... I get this weird half monophonic glitch or something. It is almost like one sound mutes the other... some times. The program is NOT in "MONO" mode.

Why does this happen? This ONLY happens when I try to sequence the MPC from an external source (this case it is a Euclidean algorithm sequencer). I can get this to sequence VSTs in Logic 9 without a hitch. It also will sequence my Volca Beat 100% of the time.

Does anyone here have any earthly clue why this might be happening to JUST the MPC? I have a feeling that I'm not getting the settings straight somewhere as sequencing anything else with this program is a breeze...

Any words of wisdom are much appreciated.
Thanks!

Multitimbral mode was introduced in JJOSXL.

Is that really what the deal is? Dang...
/facepalm

Now I am starting to think that my woes could be spawned from this satanic MIDI-to-USB cable. I tried to sequence my Volca Beats again with the same program, this time using this cheap-o MIDI interface and it choked just the same as the MPC did.

I am starting to believe that if I sequence using the MIDI on any of my "real" interfaces, it should work (just like sequencing the Volca did the first time). Guess I will be trying this later on! Hoping it works on the MPC.