fence_virtd: 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/fence_virtd - from package: fence-virtd

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

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