No sound in Mandriva with Firefox
 

I am running Mandriva 2007.1
I just try to hear the sound of an English word on the following website.

http://encarta.msn.com/dictionary

I didn't get sound.
I got the following message.
No suitable plugins were found.
How can I solve the problem?

I am using Firefox browser.
I have a 64 bit processor.
[However, sound works when I insert a Mozart CD. So the system recognizes the
sound card. The problem is with the browser.]

Try checking some configuration in about:config in Firefox. put in the search box "sound" or something like that.

No I didn't find any.