vdltodmx: 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/vdltodmx - from package: xorg-x11-server-Xdmx

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

On Debian possible default full paths are:

/usr/bin/vdltodmx - from package: xdmx-tools

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

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