vpcd: 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/vpcd - from package: powerman

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

On Debian possible default full paths are:

/usr/sbin/vpcd - from package: powerman

You may install the required package with command apt-get install {package}

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