I mean in the sound options under the system menu in-game, make sure Sound Effects is checked and the volume is up since that's the channel "SFX" is telling it to play on.
I might have typed the path wrong to the files but I thought I wrote what you had.
Try replacing the PlaySoundFile I have with one of yours like
Lua Code:
PlaySoundFile("Interface\\AddOns\\HokutoNoMonk\\sounds\\Tigereye Brew.ogg", "SFX")
to see if it'll play that, if it does then there must be some problem with how I've written the path.