jack-stdout: 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/jack-stdout - from package: jack-stdio

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

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