Make sure error reporting is enabled on your server or check the error_log for the errors.

hi michael thanks for your reply, im having this problem again in new installing, i remember i fixed it by putting this code in php.ini file but now it won't work
the code
ini_set('display_errors',1);
ini_set('display_startup_errors',1);
error_reporting(-1);
can you please help me with this ?

thanks Paul for the reply i opened the file config.php but i didn't find debug at the bottom here is what is inside the file
......................................
<?php

define('OW_DIR_USERFILES', OW_DIR_ROOT.'ow_userfiles'.DS);
define('OW_DIR_STATIC', OW_DIR_ROOT.'ow_static'.DS);
define('OW_DIR_PLUGINFILES', OW_DIR_ROOT.'ow_pluginfiles/');

define('OW_DEBUG_MODE', false);
define('OW_DEV_MODE', false);
define('OW_INSTALL_PLUGINS', false);
define('OW_PASSWORD_SALT', 'oxwall_salt_SK750');
define('OW_PROFILER_ENABLE', false);

define('OW_DIR_CORE', OW_DIR_ROOT.'ow_core'.DS);
define('OW_DIR_INC', OW_DIR_ROOT.'ow_includes'.DS);
define('OW_DIR_LIB', OW_DIR_ROOT.'ow_libraries'.DS);
define('OW_DIR_UTIL', OW_DIR_ROOT.'ow_utilities'.DS);
define('OW_DIR_PLUGIN', OW_DIR_ROOT.'ow_plugins'.DS);
define('OW_DIR_THEME', OW_DIR_ROOT.'ow_themes'.DS);
define('OW_DIR_SYSTEM_PLUGIN', OW_DIR_ROOT.'ow_system_plugins'.DS);
define('OW_DIR_SMARTY', OW_DIR_ROOT.'ow_smarty'.DS);

define('OW_USE_CLOUDFILES', false);
....................................................
which one to change to true?
i also put the code in php.ini

log_errors = on
error_reporting = E_ALL & ~E_NOTICE

but nothing happend

i did put the code you mentiond in php files in install dir
now after filling the database info i get this error

Fatal error: Class 'PDO' not found in /home/xxxx/public_html/ow_core/database.php on line 159

sometimes i get this message when i open my site
Hosting Server Requirements

Your hosting account doesn't meet the following requirements:

• PDO PHP extension not installed

Please correct these before you can proceed with Oxwall installation. Complete server requirements list and compatible hosting can be found at Oxwall.org/hosting

sometimes i get this and sometimes not, do you think if i installed this PDO PHP will work? how i do install this PDO PHP extension?

Dear Sezar, you will need to contact your hosting company so that they install PDO PHP extension for you.

Thanks Paul :)