discover-modprobe: 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:

/sbin/discover-modprobe - from package: discover

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

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