ncwa: 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/ncwa - from package: nco

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

On Debian possible default full paths are:

/usr/bin/ncwa - from package: nco

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

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