mtdump: 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/mtdump - from package: simh

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

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