nse: 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 Debian possible default full paths are:

/usr/bin/nse - from package: ns2

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

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