Samples off beat when tracked into pro tools?

I am using reason as a sound module and my mpc 2000xl as the midi sequencer. I have one vocal sample loaded into my mpc and that is the only sound that is actually coming out of my mp the rest is being triggered from reason. When I am recording the actual audio for each instrument onto the tracks in pro tools, I am listening through my monitors and everything is playing on time perfectly (vocal sample and all), however once each individual instrument has been recorded on each individual track in pro tools. I play the audio that has been recorded onto the tracks in pro tools back and the vocal sample is off beat. I use this procedure every time I make a beat and no problem before now.

I even pulled up one of my old beats that was setup the same way, to make sure it still wasn't all of my beats. I had a looped sample and vocal sample in the mpc and the rest was audio from reason, I tracked it into pro tools and no problem everything played in sync and on beat. So I don't know what I am doing wrong?

Can someone tell what they think is the problem?

Thanks