milkyplay: 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/milkyplay - from package: milkytracker

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

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