dmxreconfig: command not found

Have You tried accessing the binary with the full path?

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/dmxreconfig - 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/dmxreconfig - from package: xdmx-tools

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