Thanks blackwolf! The tscalibrate reset seems to put it back to defaults. However, it does not repair the problem with the calibration application itself (which is also previously described in this thread):
When I want to calibrate, the calibration application closes before I can finish the calibration! Immediately when I touch the first point in the upper left corner, it goes off and throws me back to the desktop. .... Hence I can not do any calibration.
It used to work fine. All I have (consciously) done since last time I calibrated was installing some 4GB of maps from the nokia US site via ovi map loader ... I guess that can't be a problem ....

Any idea if this is a know/reported bug or if there is some other process that might influence it?