named-checkconf: 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/named-checkconf - from package: bind

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

On Debian possible default full paths are:

/usr/sbin/named-checkconf - from package: bind9utils

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

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