mpdrun.py: 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/mpdrun.py - from package: mpich2

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

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