Frank, I'm pleased to hear that the quiz works on my site. It is also good to know that you got a different JCross to work on your site.
There were some problems with earlier versions of the HotPot module and PHP 5, which caused JCross and JMatch not to work. However, that was a while back now and the symptoms were that the quiz did not show at all, which seems to be different from what you reported.
If you want to be sure you have the latest version of the HotPot module for Moodle 1.6, you can download it from here:
If you continue to have problems with the quiz on your site, please send me the URL to I can see it for myself: gordon at-sign kanazawa hyphen gu dot ac dot jp
all the best