openpgp2ssh: 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/openpgp2ssh - from package: monkeysphere

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

On Debian possible default full paths are:

/usr/bin/openpgp2ssh - from package: monkeysphere

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

Error in other languages:
openpgp2ssh: bevel nie gevind nie
openpgp2ssh: comandă negăsită
openpgp2ssh: comando não encontrado
openpgp2ssh: commande introuvable
openpgp2ssh: command not found
openpgp2ssh: käsku ei ole
openpgp2ssh: không tìm thấy lệnh
openpgp2ssh: komanda nerasta
openpgp2ssh: Kommando nicht gefunden.
openpgp2ssh: kommandot finns inte
openpgp2ssh: komut yok
openpgp2ssh: nie znaleziono polecenia
openpgp2ssh: níor aimsíodh an t-ordú
openpgp2ssh: no se encontró la orden
openpgp2ssh: no s'ha trobat l'ordre
openpgp2ssh: opdracht niet gevonden
openpgp2ssh: parancs nem található
openpgp2ssh: perintah tidak ditemukan
openpgp2ssh: príkaz nenájdený
openpgp2ssh: příkaz nenalezen
openpgp2ssh: команда не найдена
openpgp2ssh: командата не е открита
openpgp2ssh: 命令找不到
openpgp2ssh: コマンドが見つかりません