I just installed FCP 5.1 and can't import files from a P2 that were transferred to my hard drive from a demo camera I shot with. I opened the P2 import window, navigated to the folder with MFX files and they are greyed out. I have version 1.01 of the P2PC card install software and version 7.04 of QT, and the most recent OSX update.
There is a CONTENTS folder with an AUDIO, CLIP, ICON, PROXY (nothing in it), VIDEO (where MFX files are), and a VOICE folder in it, and there is a LASTCLIP.TXT file. A sales person transferred the data off the P2 to my hard drive, so I assume everything I need to import the MFX files in to FCP 5.1 is there.