mlclient: 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/mlclient - from package: mlterm-tools

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

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