pmmyplay: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

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/pmmyplay - from package: pmacct

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