ncl: 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/ncl - from package: ncl

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

On Debian possible default full paths are:

/usr/bin/ncl - from package: ncl-ncarg

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

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