arb_sync-WaitSync-errors: 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-WaitSync-errors - from package: piglit

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

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