I asked a question earlier and the answer I got didn't help. It's getting to be an old question, so someone please answer it. Here it is: http://Pokemondb.net/pokebase/89748/please-help-leafgreen-troubles
Your LeafGreen copy is not a legit copy of the game. Because of that, if you have any game with the LeafGreen copy in the GBA slot, it wipes the memory of the DS game up top. This is also the reason why the messages showed up.