I have had this problem before. At some point in the data transfer, either when the contents of the P2 card were copied over to your hard drive or when you imported the P2 footage into FCP, the data was corrupted. When I’ve had this problem I either re-transfer the data from the P2 card (assuming it hasn’t been wiped) or import it again from the copied folders. This always solves the problem. I’ve never seen the actual source data from the P2 card corrupted, which is nice. If you’re using a less than stellar hard drive (Maxtor, WD, etc) then it’s been my experience that the instances of these data corruptions increase. I rarely if ever have problems when transferring to CalDigit or G-Raid drives.
This is why it’s important to import your p2 into FCP or your NLE before wiping the cards — to make sure there weren’t any errors in the transfer. Good luck and let us know if this helps!
Peter