mbsubmit: 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/mbsubmit - from package: ears

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

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