pmrep: 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/pmrep - from package: pcp-system-tools

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

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