arb_sync-sync-initialize: 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/arb_sync-sync-initialize - from package: piglit

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

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