arb_separate_shader_object-ValidateProgramPipeline: 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_separate_shader_object-ValidateProgramPipeline - from package: piglit

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

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