error_resilient: 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/bin/error_resilient - from package: libvpx-utils

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

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