depthfunc: 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/depthfunc - from package: piglit

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

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