A friend of mine just picked up a used copy of Leaf Green(Pokemon) to play on his DS lite. The game however gave him some really strange errors and I was wondering if anyone had a clue as to what they might mean.

This error comes up when the game is started:
"1M sub-circuit board is not installed"

You can go past this error and start the game, but when you go to save this error appears:
"Save error, Please exchange the backup memory."

I was also wondering how do GBA games save, do they have a backup battery?