mactelnet: 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/mactelnet - from package: mactelnet-client

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

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