bluemon-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/bin/bluemon-client - from package: bluemon

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

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