arb_clear_buffer_object-sub-simple: 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/arb_clear_buffer_object-sub-simple - from package: piglit

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

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