modplugplay: 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/modplugplay - from package: modplug-tools

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

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