start_udev: 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 CentOS possible default full paths are:

/sbin/start_udev - from package: udev

You may install the required package with command yum install {package}

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