kgpg: 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/kgpg - from package: kdeutils

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

On Debian possible default full paths are:

/usr/bin/kgpg - from package: kgpg

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

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