by qh » Sat May 03, 2008 8:49 am

You can try to install a new "Quicktime" (ver. 7+) plug-in from:
(I use firefox 2 and Quicktime 7 and it seems to work ok.)

http://www.apple.com/quicktime/download/

I think maybe your quicktime (audio interface) was a little updated.
After downloading, reboot your pc and check if you can hear the audio from the dictionary site.

You could also try it from the other computer to double check it too.

Hope this works.