pgpgpg: 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 Debian possible default full paths are:

/usr/bin/pgpgpg - from package: pgpgpg

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

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