ext_fog_coord-modes: command not found

Have You tried accessing the binary with the full path?

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/ext_fog_coord-modes - from package: piglit

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