op-check-perfevents: 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/op-check-perfevents - from package: oprofile

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

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