You can calibrate the Touch Screen through the Nintendo DSi system settings.
How to recalibrate the Touch Screen:
- On the System Settings Menu, go to page 3, then select "TOUCH SCREEN."
- Touch the orange circle with the stylus, then repeat each time it moves.
- When the calibration is complete, four orange circles will appear on the screen. Tap them to test the calibration, then select "OK" to save the settings.