vao-02: 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/vao-02 - from package: piglit

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

Error in other languages:
vao-02: bevel nie gevind nie
vao-02: comandă negăsită
vao-02: comando não encontrado
vao-02: commande introuvable
vao-02: command not found
vao-02: käsku ei ole
vao-02: không tìm thấy lệnh
vao-02: komanda nerasta
vao-02: Kommando nicht gefunden.
vao-02: kommandot finns inte
vao-02: komut yok
vao-02: nie znaleziono polecenia
vao-02: níor aimsíodh an t-ordú
vao-02: no se encontró la orden
vao-02: no s'ha trobat l'ordre
vao-02: opdracht niet gevonden
vao-02: parancs nem található
vao-02: perintah tidak ditemukan
vao-02: príkaz nenájdený
vao-02: příkaz nenalezen
vao-02: команда не найдена
vao-02: командата не е открита
vao-02: 命令找不到
vao-02: コマンドが見つかりません