jack-transport: 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-transport - from package: jack-tools

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

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