pvck: 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:

/sbin/pvck - from package: lvm2

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

On Debian possible default full paths are:

/sbin/pvck - from package: lvm2

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

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