depth-level-clamp: 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/depth-level-clamp - from package: piglit

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

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