kmdr-plugins: 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/kmdr-plugins - from package: kdewebdev

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

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