MBA Won't recognize class 10 SD card from card reader or from Nikon D5100

I simply can't take any of my pictures off of my SD card. I've tried using the USB cable that came with the camera itself, as well as a USB card reader. iPhoto, and the laptop itself does not recognize the card, or that there is any device mounted at all. I've also tried checking "External Disks" in Finder Preferences, didn't seem to work.

Not quite sure what to do at this point, I've poked around in various forums and it seems to be a semi-frequent asked question, any tips? Or other modes of getting my photos to my MBA?