cracklib-check: 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 CentOS possible default full paths are:

/usr/sbin/cracklib-check - from package: cracklib

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/sbin/cracklib-check - from package: cracklib-runtime

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