Error playing sound

I am trying to listen to audio files in PDF:s for my language class, but I keep getting this error when I press the audiobutton "Acrobat has encounted an error while playing this mediaclip". I have allowed acrobat to listen to the sound - which it asked me to do. I have tried changing the preference settings for security, multimedia and javascript. Still can't listen to it. Tried on my IPAD, tried using different browsers in the web, nothing works. How do I resolve this issue?http://skjol.menntamidja.is/skjol/TMT/ifa/bok1/Bok1Hljod/kafli1.pdf
This is the PDF I am trying to listen to.

Thanks for any help in advance,
Filippa