mobj_dump: 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/mobj_dump - from package: libbluray

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

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