dvdauthor: 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/dvdauthor - from package: dvdauthor

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

On Debian possible default full paths are:

/usr/bin/dvdauthor - from package: dvdauthor

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

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