gnome-nettool: 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/gnome-nettool - from package: gnome-nettool

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

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