very probably a contact problem with the r4ds and ds that cant read it . is there any dust or dirt in the slot of the ds ? if not then the paper trick might work , as follows - cut a piece of thin card the same width as your r4ds but about 1 inch longer than your r4ds . now put the card on the side of the r4ds sticker and insert them both into your ds . what this does is very slightly push the r4ds closer to the cotacts inside your ds . woof811.