mlmmj-list: 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/mlmmj-list - from package: mlmmj

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

On Debian possible default full paths are:

/usr/bin/mlmmj-list - from package: mlmmj

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

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