vobcopy: 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/vobcopy - from package: vobcopy

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

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