dmxtodmx: 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/dmxtodmx - 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/dmxtodmx - from package: xdmx-tools

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

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