arb_framebuffer_object-negative-readpixels-no-rb: 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_framebuffer_object-negative-readpixels-no-rb - from package: piglit

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

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