Dear Leo,
thanks for sending the jcr file. It was the final piece of the puzzle for me.
Interestingly the problem was not the umlaut in the quiz, but the umlaut "u" in your surname. Hot Potatoes encodes ALL the accented and multibyte charaters used in the readings, questions and answers, so I thought there was no need to worry about unicode. However, there are a few fields that are not encoded (the "registered to" field being one of them). I have fixed lib.php to handle these fields, and you can see your quiz working here:
http://bateson.kanazawa-gu.ac.jp/moodle/mod/hotpot/view.php?id=1796
However, I would like to ask you to wait a day or two before downloading the latest version of the module, because in the last few days I have been working with Tom so that we can release "HotPot v2" on Monday. (I will start another thread about this important topic)
many thanks as always for your continuing help and good humor!
Gordon