argonaut-client: 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/sbin/argonaut-client - from package: argonaut-client

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

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