mixing-clip-distance-and-clip-vertex-disallowed: 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/mixing-clip-distance-and-clip-vertex-disallowed - from package: piglit

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

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