checkapoppw: 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/checkapoppw - from package: checkpw

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

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