decibel-audio-player: 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/decibel-audio-player - from package: decibel-audio-player

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

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