nc.traditional: 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:

/bin/nc.traditional - from package: netcat-traditional

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

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