Ouch. That looks like a corrupted file system on your card. If you got a valid backup from your card you should reformat the memory card and then copy all files back onto it. If not, backup all files (which are still readable) to a PC and then reformat the card, copy all other valid files back and reinstall the missing files.
Answer to the "grab" statement: Programs like CardExport or any other program which allows reading the memory card via USB connection will hide the memory card from your device while active by "grabbing" access to the memory card.
*** bye for now AP756 ***