Hi Susan,
Does the card shows in the Finder?
If not, open the Disk Utility and see if it shows up there .
If the volume is grayed try to mount it:
If the card mounts in the Finder, copy the MP4 files to your HD.
Then with the SONY Clip Browser you can rebuild a BVAP folder and use the SONY Transfer Tool to log and transfer.
If you find any grayed MP4 file in the card, forget about it. is corrupted.
So far I've been able to recover the files from the SDCH cards.
From the SxS cards is a real nightmare.
rafael
http://www.nagavideo.com