dfbtest_window_flip_once: 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/dfbtest_window_flip_once - from package: directfb

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

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