gpg-key2ps: 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/gpg-key2ps - from package: signing-party

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

Error in other languages:
gpg-key2ps: bevel nie gevind nie
gpg-key2ps: comandă negăsită
gpg-key2ps: comando não encontrado
gpg-key2ps: commande introuvable
gpg-key2ps: command not found
gpg-key2ps: käsku ei ole
gpg-key2ps: không tìm thấy lệnh
gpg-key2ps: komanda nerasta
gpg-key2ps: Kommando nicht gefunden.
gpg-key2ps: kommandot finns inte
gpg-key2ps: komut yok
gpg-key2ps: nie znaleziono polecenia
gpg-key2ps: níor aimsíodh an t-ordú
gpg-key2ps: no se encontró la orden
gpg-key2ps: no s'ha trobat l'ordre
gpg-key2ps: opdracht niet gevonden
gpg-key2ps: parancs nem található
gpg-key2ps: perintah tidak ditemukan
gpg-key2ps: príkaz nenájdený
gpg-key2ps: příkaz nenalezen
gpg-key2ps: команда не найдена
gpg-key2ps: командата не е открита
gpg-key2ps: 命令找不到
gpg-key2ps: コマンドが見つかりません