Error 500
i GET THIS ERROR WHEN CLICKING ON CUSTOMIZE THIS PAGE IN THE "MAIN " PAGE 

The people from the hosting told me to talk to oxwall people about it , Pls Help me 
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.