packetdiag: 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/packetdiag - from package: python-nwdiag

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

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