wbemain: 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/bin/wbemain - from package: sblim-wbemcli

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

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