mpdallexit: 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/mpdallexit - from package: mpich2

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

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