network-config: 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/network-config - from package: network-config

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

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