blending-in-shader: 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/blending-in-shader - from package: piglit

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

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