I do not understand, please help me I am since 3 days offline, I lose my client, that's my problem:

enable debug mode the instructions provided on the error page, you'll get actual error, provide the error here so we could assist you

Thanks...I have it made what written in error, but that will come back the same problem..

Error 500
Internal Server Error.

If you are the site admin, click here for details (+)

Something went wrong!
To get the error details follow these steps:
- Open ow_includes/config.php file and set DEBUG_MODE to true
- Reproduce your last action.

You probably made debug mode ON in the wrong place, please provide screesnhot of your config. php file 

of that part

define('OW_USE_CLOUDFILES', false);
if ( defined('OW_CRON') ){    define('OW_DEBUG_MODE', false);    define('OW_DEV_MODE', false);    define('OW_PROFILER_ENABLE', false);}else{    /**    * Make changes in this block if you want to enable DEV mode and DEBUG mode    */
    define('OW_DEBUG_MODE', false);    define('OW_DEV_MODE', false);    define('OW_PROFILER_ENABLE', false);}

Topic was moved from General Questions.

Thanks...

Gjovani, enable debug mode and provide us with the actual error. So we could assist you further.