vmpsd: 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/vmpsd - from package: vmpsd

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

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