dmxresize: 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/dmxresize - 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/dmxresize - from package: xdmx-tools

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

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