pmafm: 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/pmafm - from package: pcp

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

On Debian possible default full paths are:

/usr/bin/pmafm - from package: pcp

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

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