ilan: 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:

/usr/sbin/ilan - from package: ipmiutil

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

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