Hi there,
You will need to format the card for the camera to read\write onto it.
Simply pop it into your camera, hit the menu button and scroll through the menu until you find 'format'. It will most probably prompt you 'all data on the card will be lost' but as there is nothing there anyway just hit OK.
As soon as its complete you can now use the card.
Hope that helps, although if you are stuggling to find the format option in the menu a quick look in the camera manual will help you out.