pmdefaults: 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/pmdefaults - from package: portmidi-tools

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

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