isbufferobj: 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/isbufferobj - from package: piglit

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

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