Recording an MPC 1000 into PT 9

[MidnightFlyer]

This is a strange thing that happens with PT 9.0.5 which never happened with PT 5.2.1 on OS9, which I used for many years.

When I play the pads on the MPC in "record enable" in PT 9, each sample distorts. Even with the levels way down, there's distortion on all my samples.
But if I take it out of "record" it plays fine with no distortion.

I record from the MPC by going through the stereo outs, by guitar cables, into my preamps. This was how I was doing it for years with no problems. And there is no distortion happening anywhere in the chain. So it is beyond me how this distortion keeps happening when I record, but it's fine when NOT record-enabled, and it never happened before I upgraded to PT 9.

any guesses?

iMac, 2.7GHz i5, Profire 610, Benchmark DAC, Rosetta, Brent Averill preamps