2 sound files missing or in a bad format!!!

[sprite]

Hi,
The following error message appears to me when i want to start a new game in Call of
Duty:United Offensive:"2 sound file(s)are missing or in a bad format"....i have uninstalled
the game,as activision's troublshooting database suggested, and deleted its folder and then reinstalled it(i just got it yesterday,so
i have no third party maps\skins\mods yet.)... BTW:COD worked on my PC without any problems
but i don't know why the "United Offensive" didn't  

my system specs are:

-2.8 G.H. intel pentium4.
-nVidia gefoorce4 MX4000.
-Realtek AC'97 Audio.
-512 MB of RAM.
-LG CD-ROM CRD-8525B.
-Windows XP Professional.

thanks...

[Raptor]

Does this concern a legal copy? If not.. Well then you know what's wrong. If it does, exchange your copy for a new one.