arb_separate_shader_object-UseProgramStages-non-separable: 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-UseProgramStages-non-separable - from package: piglit

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

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