mbexamine: 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/lib/cyrus/bin/mbexamine - from package: cyrus-common

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

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