I have a problem of semitone on my KeyLab
1/ Go to the "transposition Mode" directly on the keyboard (Click Octave + and Octave - at the same time dureing 5 seconds)
2/ Change the Value of the semi tone to 0 by pressing Octave + and Octave -
You may have the wrong Firmware, you can go on this page to update to the correct firmware.
If still a problem, you can contact Technical support