ifwum: 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/ifwum - from package: ipmiutil

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

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