mutual: 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/mutual - from package: yagiuda

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

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