This is not really a reply, but I have a problem with the same type of card.
My MacBook Pro has stopped recognizing RAW format images from my Sony a55 camera, Memory Stick Pro HG Duo cards. I have two cards of this type and the problem exists with respect to both. It is not a bad card - my Canon printer reads the images from this card and the MacBook reads jpeg images from this card in the camera via the USB connection. It is not a problem with the camera-computer USB connection because neither of my two card readers let the computer read this card either. My operating system (OS X 10.6.8) supports RAW from my camera according to the Apple support website.
Now it gets curioser and curioser. The MacBook recognizes RAW images from my Canon camera (SD card) when connected to that camera with the USB cord. And - when I put the SD card from my Canon in my Sony (dual card capability) shoot RAW images, and then plug the card into the SD card slot in the MacBook, it shows up as Canon and the RAW images download, although they won't download when I connect the Sony with that SD card via the USB cord - this connection shows up as a Sony.
My Sony is set at RAW and as Mass Storage.
Now, I know that one solution is to get SD cards for the Sony and write off the investment in the two 16 GB Memory Sticks. However, I'm retired, and reluctant to adopt the "throw money at it" solution if there is another solution.
Any thoughts would be appreciated.