White Noise on PT 8.1 mac session import

[application4]

Here's what's happening:

I'm opening a session on my W7 (64bit) HD2 rig running PT 8.1 cs2. (I know... 64bit is still in beta...)

The session was created on a Intel Mac running PT HD 8.1.
Waveforms display correctly but all the audio tracks output loud white noise.

Other sessions on the same drive open and run fine.
If I audition the audio files in the audio import window they play back fine, and if I audition them in W7 preview player they're fine too.

Have tried 'import session data' and importing the files into a fresh blank session. Same problem occurs.

The audio files import fine into Ableton Live running stand alone and playback with no problems.

Any thoughts?
Thanks.

[avasound]

Hi!
Simply open session and SAVE COPY IN...with copy all audio files. Then open new session and all be OK!

[application4]

Thanks for the tip but I've tried that I'm afraid, and the same problem occurred.
I gave up and opened the audio in Ableton Live which worked perfectly...
Weird.