it took me a long time to figure out how to playback from the HD-P2, and I was going crazy trying to do it. then I figured it out.
I'm assuming that you used an external A/D, so you had the signal source set to S/PDIF, and also the clock source set to S/PDIF (as you should have it set when recording from S/PDIF. unless you were syncing with another external clock, and then you could set the clock source to "word clock")
anyway, to play back the files, you don't have an incoming S/PDIF source, so there is no clock information.
Go to the project settings menu, and change the clock source to internal. Once I did that, it played back just as it should...
that was the problem for me, hopefully it takes care of it for you