object_purgeable-api-pbo: 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/object_purgeable-api-pbo - from package: piglit

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

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