mimedump: 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/mimedump - from package: perl-MIME-tools

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

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