Hi Brecht.
Your case reference number is 355811 should you need to contact us directly regarding this issue
Please could you try and remove the power cable to this ActivBoard and leave it for a few minutes then reconnect the cables and try the calibrate? What is the current length of the USB cable which you are using? If possible, please try a shorter USB cable and see if the same issue happens.
Please try using the 25 point calibration, does this work? What happens when you try and calibrate on the crosses on the calibration screen?
I look forward to your response,
Adam
Promethean Technical Support