pmpgplay: 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/pmpgplay - from package: pmacct

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

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