drbl-gen-pxe-nbi: 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/share/drbl/sbin/drbl-gen-pxe-nbi - from package: drbl

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

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