gpu_shader4_attribs: 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/gpu_shader4_attribs - from package: piglit

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

Error in other languages:
gpu_shader4_attribs: bevel nie gevind nie
gpu_shader4_attribs: comandă negăsită
gpu_shader4_attribs: comando não encontrado
gpu_shader4_attribs: commande introuvable
gpu_shader4_attribs: command not found
gpu_shader4_attribs: käsku ei ole
gpu_shader4_attribs: không tìm thấy lệnh
gpu_shader4_attribs: komanda nerasta
gpu_shader4_attribs: Kommando nicht gefunden.
gpu_shader4_attribs: kommandot finns inte
gpu_shader4_attribs: komut yok
gpu_shader4_attribs: nie znaleziono polecenia
gpu_shader4_attribs: níor aimsíodh an t-ordú
gpu_shader4_attribs: no se encontró la orden
gpu_shader4_attribs: no s'ha trobat l'ordre
gpu_shader4_attribs: opdracht niet gevonden
gpu_shader4_attribs: parancs nem található
gpu_shader4_attribs: perintah tidak ditemukan
gpu_shader4_attribs: príkaz nenájdený
gpu_shader4_attribs: příkaz nenalezen
gpu_shader4_attribs: команда не найдена
gpu_shader4_attribs: командата не е открита
gpu_shader4_attribs: 命令找不到
gpu_shader4_attribs: コマンドが見つかりません