pmkscan: 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/pmkscan - from package: pmk

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

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