nice to see you here. It was great to meet you in Paris !
Thank for making the quiz and audio files available to investigate this issue. The software was not sure where to find the URL to convert from a relative URL to an absolute URL, so it guessed. Unfortunately it chose the wrong place to look. It assumed the audio URL would be the last part of the url specified in the <param name="movie" ...> tag. Unfortunately, this is the wrong place to look in your quizzes.
After some thought, I decided to make the software look for one of the following named arguments in the query string of url:
I confirmed that this allows the correct transformation of relative URLs to absolute URLs in your quizzes.
You did not say which version of Moodle you are using, nor which module you were using, but convenience here are links to the two modules I have fixed:
I have *not* modified the HotPot module for Moodle 1.9, because from what I can see, it already does the right thing. If you disagree, please let me know and I will investigate further.