IMPORTANT UPDATE NOTICE!!!
The sound files go in the "vo" folder, not in the "Player" folder. Disregard from reading the "Readme" and put the sound files in the "vo" folder like this:
steam \ steamaps \ username here \ team fortress 2 \ tf \ sound \ vo
Sorry for the mistake guys, and have fun!
(Note: There are 2 Demoman sound files under "demoman_eyelandertaunt." Don't delete those, they are 2 different sound files, even so they sound the same, one is different from the other.)