packetforge-ng: 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/packetforge-ng - from package: aircrack-ng

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

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