arb_viewport_array-clear: 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_viewport_array-clear - from package: piglit

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

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