Poly/Mono and Looong Samples

So I played my bass (through a preamp ofcourse) into my MPC2500. It sounds great. I have a drum pattern and Sample chopped and laid out.. it also sounds great.
When I assign the recording of my bass to a pad and press play, for whatever reason it only plays the sample of the bass until bar 6 then it cuts off. When i play the sample by itself with the bass, both the sample and the bass i played play all the way through. but when i add the drums, the bass stops playing at bar 6.
the only mute group i have active is on pads 1,3, and 9 on my drum program. but i created a whole seperate program for the one pad i put the bass recording on.
I just want my bass to play all the way through with the drums...
should i just chop the bass i played in two and plug it in a bar 5?
help please!!!

Get JJOS2XL if you don't already have it, and use the audio tracks. These are designed for exactly your style of workflow (mine too). You can just track something in alongside your beat and it stays right where you put it.

That said, there's no reason I can think of why what you're doing shouldn't work also. Does the sample play all the way through from the trim screen? Also check your amp and filter envelopes. And make sure it's set to "one shot" Try it on a different pad / different track in case you have something else in there that could be cutting it off. Get into step edit and look around.

I bet you're running out of polyphony.

The MPC is only capable of 32 voices of polyphony which means 32 sounds in mono or 16 sounds in stereo at once. Thats what it sounds like to me. Try converting some of you're samples to mono if they don't have to be in stereo.

You can only have 32 monophonic and monoaural sample lines going on at the same time. I always start with this kinds of setting and never fall in this issue.
Use stereo and/or polyphonic ovelap ONLY where you really need to. With wrong settings you can literally kill whole 32 polyphony striking just ONE pad ONCE, so it's not about the machine..