fp-rfl: 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/lib64/piglit/bin/fp-rfl - from package: piglit

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

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