dvdxchap: 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/dvdxchap - from package: ogmtools

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

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