Why does r4i not work in my daughters dsi?

I have just brought r4i's for all my kids, and the only dsi that it doesn't work on is my daughters. I have tried her card in the other kids dsi's and it works, and vice verse, but just doesn't want to work on hers, I have reformatted the card and still it comes up with an error on the screen saying "an error has occurred press and hold the power on to turn the system off, please refer to manual" which I have done and it hasnt given me many options, but done what it has told me to do. Can anyone please help. Thanks