I am getting some flak from my 13 year daughter...

She has a PS2 (the nice blue one) with two matching controllers. I bought her a generic 8mb card so that she could save game states. She complains that most games will not save, but one will (Harry Potter).

A week ago she received a new genuine sony 8mb card with the same results. Is it likely the ps2 is faulty or is there something that can cause this problem?