Session share issue, PT10 Mac to PT10 express PC

[Big Mother]

I am trying to share a session with a friend, I have PT 10 on a Mac, he has PT 10 Express on a PC. I did the usual "Save Session Copy", made sure audio files was checked. The resulting session copy opens fine for me, all audio files in place, looks fine.
When he tries to open it, session comes up fine, but no audio files are linked (but he does see the empty regions). Audio files are in the audio file folder, but not importing into the session.
Trying to explain how to relink the files over the phone (he is new to PT and a few states away) is hard, would rather it just pop up like I expect it to.

Odd that the sessions he sent to me (from PC to Mac) works just fine.

Any idea what I might be doing wrong?


MacBookPro5,2 10.6.8 - PT 10.3.2