update-cracklib: 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/sbin/update-cracklib - from package: cracklib-runtime

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

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