My memory card for my d3100 won't format, I've

Have you actually formatted the card in the camera ? Just copying the photos does not remove them from the card

What size is the memory card. If it's larger than 4GB then it won't work in the 5118.
Try using another card. Don't format it in your computer but do format it in the camera before trying to take pictures.

There is a tab on the memory card so you will you need to remove it from the camera and change the position of this tab to "unlock" it. DO NOT format the card until you've BACKED UP your files from it (typically to a PC or USB drive (stick or external hard drive).

Actually, you still might be able to get those photos back, even though they've been erased. Try not to take any more pics until you've recovered your photos, take the card out of the camera. This is to reduce the chance of you overwriting some of your "lost" photos. There are many good freeware photo recovery software options that may help you recover your photos. This article reviews and outlines several of the better ones.
This sounds like the problem may have occurred because you might not have formatted the card in your camera as recommended by the manufacturer. If true, after you've recovered your photos, format the card in your camera using the camera's format feature. This will prevent this from happening again.

The only time I've see this happen, is when someone uses a memory card that's too large for that model of phone.

That phone can only handle a 4gb max memory card. Anything larger won't work, and can lock up the phone.

The camera takes SD cards up to 2GB (not SDHC cards). If you've been taking pictures using the camera's internal memory, you must first get rid of those pics. With no card in the camera, go into the menu and find "format" and follow the on-screen instructions. Then, insert your new card and go through the "format" routine again to prepare the new card.

Right click the Folder of your USB, click on 'Format'. A window should come up; just click on 'Start' - located on the bottom.

Look on this forum:

http://supportforums.blackberry.com/t5/BlackBerry-Curve/Problem-updating-device-software-quot-Fatal-error-quot/td-p/82515

Hi, The reason neither 4GB card will format is because that camera is only able to support, at most, a 2GB card. I'd suggest returning the 4GB card and getting another 2GB one.

Put the SD card in a stand alone card reader, and copy the data off it to your computer. Next, format the SD card, and put it back in your phone.