nsec3hash: 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/sbin/nsec3hash - from package: bind

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

On Debian possible default full paths are:

/usr/sbin/nsec3hash - from package: bind9

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

Error in other languages:
nsec3hash: bevel nie gevind nie
nsec3hash: comandă negăsită
nsec3hash: comando não encontrado
nsec3hash: commande introuvable
nsec3hash: command not found
nsec3hash: käsku ei ole
nsec3hash: không tìm thấy lệnh
nsec3hash: komanda nerasta
nsec3hash: Kommando nicht gefunden.
nsec3hash: kommandot finns inte
nsec3hash: komut yok
nsec3hash: nie znaleziono polecenia
nsec3hash: níor aimsíodh an t-ordú
nsec3hash: no se encontró la orden
nsec3hash: no s'ha trobat l'ordre
nsec3hash: opdracht niet gevonden
nsec3hash: parancs nem található
nsec3hash: perintah tidak ditemukan
nsec3hash: príkaz nenájdený
nsec3hash: příkaz nenalezen
nsec3hash: команда не найдена
nsec3hash: командата не е открита
nsec3hash: 命令找不到
nsec3hash: コマンドが見つかりません