ksvalidator: 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 CentOS possible default full paths are:

/usr/bin/ksvalidator - from package: pykickstart

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

On Debian possible default full paths are:

/usr/bin/ksvalidator - from package: python-pykickstart

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

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