isinf-and-isnan: 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/isinf-and-isnan - from package: piglit

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

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