audio compression format

all the sounds in my computer work on everything except when I go for conference call (Yahoo) to hear the people talk on the mic this comes ups and says..."this computer does not support the required audio compression format"... Now what does that mean, and how do I fix it. it's inspiron 1525 vista home premium 32 bit. Hope you can Help!!! Thanks

I have got one link but I am hesitant to rely on it.

http://www.bytescribe.com/down.....nstall.exe