ocs-restore-mbr: command not found

Have You tried accessing the binary with the full path?

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/sbin/ocs-restore-mbr - from package: clonezilla

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