nw: 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/nw - from package: netrw

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

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