I'm trying to backup a card I used to shoot AVCHD footage. I shot it a while ago so I don't have the original card. When i drag it in finder, it starts fine, then gets super slow, then eventually i get the message, "The Finder cant complete the operation because some data in BDMV cant be read or written. The card though works fine when I try to import it into FCP 7, so I don't think the card is corrupted. Any ideas?