Liverpool 7 and any others having problems,
As i found out from downloading the chant packs windows vista, or any other for that matter dont have the capabilities to 'unzip' .RAR files (the file type the chants are downloaded in)
You therefore have to download an .RAR extraction application, a simple type into google brings up some, eg. ALZip, Bit Zipper or any other application that can compess .RAR files.
Once downloaded, the .RAR file that the chants are in can simply be opened into the application, within 10-15 seconds the files are 'turned' (not really sure what the technical term is) into mp3 files.
From there you can insert your USB, transfer the file over to PS3 by coping all the chants, it took me a while (about 180) but ive ended up with a huge selection.
PES 2010 only has the capability of storing 64 chants on the game, i really dont know why so few, but what ive done and propose to others is, from the selection you have - Make a playlist called "KONAMI_PES"
Listen to the hundreds of chants you have and select specific ones you want to be in the playlist. Once 64 have been selected open the game, go to edit, edit team and cheering stance, you can then select upto 5 chants per team.
Hope this helps