Yes, if you own a legitimate copy of PES 6. The file is part of the game data. Downloading it as a replacement for your own copy falls under fair use for archival and repair purposes. Do not redistribute it as part of a full game.
Many users mistakenly believe that “original” means outdated. On the contrary, here is why you should download and use the authentic 0_sound.afs : Download 0-sound-afs Pes 6 Original
After a fresh installation or a manual file move, the dat folder is missing its audio components. Yes, if you own a legitimate copy of PES 6