How do you unprotect a sim card of a camera

Is the card removable? If it is, take the card out and see if it has a write protect switch located on it. Slide the switch to the opposite direction of where it's at and that should unlock the card.
 
Every SD card has a little switch on the side that has a lock > pointing down on it (every card that I have seen/used has it locked in the down position.) if that little switch is down, slide it up, which will unlock the card, if you need more help, I can take some photos and do a little tutorial for you.