mmval: 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/mmval - from package: stda

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

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