stencil-drawpixels: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

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/stencil-drawpixels - from package: piglit

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