fishsound-encode: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/bin/fishsound-encode - from package: libfishsound-tools

You may install the required package with command yum install {package}
Error in other languages:
fishsound-encode: bevel nie gevind nie
fishsound-encode: comandă negăsită
fishsound-encode: comando não encontrado
fishsound-encode: commande introuvable
fishsound-encode: command not found
fishsound-encode: käsku ei ole
fishsound-encode: không tìm thấy lệnh
fishsound-encode: komanda nerasta
fishsound-encode: Kommando nicht gefunden.
fishsound-encode: kommandot finns inte
fishsound-encode: komut yok
fishsound-encode: nie znaleziono polecenia
fishsound-encode: níor aimsíodh an t-ordú
fishsound-encode: no se encontró la orden
fishsound-encode: no s'ha trobat l'ordre
fishsound-encode: opdracht niet gevonden
fishsound-encode: parancs nem található
fishsound-encode: perintah tidak ditemukan
fishsound-encode: príkaz nenájdený
fishsound-encode: příkaz nenalezen
fishsound-encode: команда не найдена
fishsound-encode: командата не е открита
fishsound-encode: 命令找不到
fishsound-encode: コマンドが見つかりません