dumpreg: 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/dumpreg - from package: svgalib

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

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