update-oui: 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/update-oui - from package: ieee-data

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

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