pmdbg: 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/pmdbg - from package: pcp

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

On Debian possible default full paths are:

/usr/bin/pmdbg - from package: pcp

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

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