mp3val: command not found

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

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

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 Debian possible default full paths are:

/usr/bin/mp3val - from package: mp3val

You may install the required package with command apt-get install {package}

Error in other languages:
mp3val: bevel nie gevind nie
mp3val: comandă negăsită
mp3val: comando não encontrado
mp3val: commande introuvable
mp3val: command not found
mp3val: käsku ei ole
mp3val: không tìm thấy lệnh
mp3val: komanda nerasta
mp3val: Kommando nicht gefunden.
mp3val: kommandot finns inte
mp3val: komut yok
mp3val: nie znaleziono polecenia
mp3val: níor aimsíodh an t-ordú
mp3val: no se encontró la orden
mp3val: no s'ha trobat l'ordre
mp3val: opdracht niet gevonden
mp3val: parancs nem található
mp3val: perintah tidak ditemukan
mp3val: príkaz nenájdený
mp3val: příkaz nenalezen
mp3val: команда не найдена
mp3val: командата не е открита
mp3val: 命令找不到
mp3val: コマンドが見つかりません