depth-tex-modes: 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-tex-modes - from package: piglit

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

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