gpk-install-package-name: 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/gpk-install-package-name - from package: gnome-packagekit

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

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