Sorry, back again here.The first failure is that it's not calibrating properly. From what I can see, it's trying to convert JPG (case sensitive) to ppm files. At the end of the script, it deletes the PPM files, so the first thing I'd check is that it is actually making those conversions in the first place etiher by commenting out the cleanup section or just watching the file manager when you run the script. Also check the name of the calibration image. It's looking for calibration.JPG. If you are doing it differently, change the configuration as appropriate.
I checked filenames and they were OK.
In file manager I get all the JPG files converted to ppm (big file size); but the ...corrected.ppm files are 0 bytes. The remaining files are calibration.bin (0 bytes too) and preprocess.log
Imagemagick is installed.
I used your Debian Post-Install Script (in case my installation of ppmunwarp went wrong), but it happens the same.