xenpvnetboot: 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/lib/xen-4.4/bin/xenpvnetboot - from package: xen-utils-4.4

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

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