exchange2mbox: 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/exchange2mbox - from package: openchange-client

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

On Debian possible default full paths are:

/usr/bin/exchange2mbox - from package: openchangeclient

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

Error in other languages:
exchange2mbox: bevel nie gevind nie
exchange2mbox: comandă negăsită
exchange2mbox: comando não encontrado
exchange2mbox: commande introuvable
exchange2mbox: command not found
exchange2mbox: käsku ei ole
exchange2mbox: không tìm thấy lệnh
exchange2mbox: komanda nerasta
exchange2mbox: Kommando nicht gefunden.
exchange2mbox: kommandot finns inte
exchange2mbox: komut yok
exchange2mbox: nie znaleziono polecenia
exchange2mbox: níor aimsíodh an t-ordú
exchange2mbox: no se encontró la orden
exchange2mbox: no s'ha trobat l'ordre
exchange2mbox: opdracht niet gevonden
exchange2mbox: parancs nem található
exchange2mbox: perintah tidak ditemukan
exchange2mbox: príkaz nenájdený
exchange2mbox: příkaz nenalezen
exchange2mbox: команда не найдена
exchange2mbox: командата не е открита
exchange2mbox: 命令找不到
exchange2mbox: コマンドが見つかりません