cdvdcontrol: 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/cdvdcontrol - from package: qpxtool

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

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