dumpkeys: 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:

/bin/dumpkeys - from package: kbd

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

On Debian possible default full paths are:

/bin/dumpkeys - from package: kbd
/usr/bin/dumpkeys - from package: kbd

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

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