Introduction

These errors may appear when you enter the Theme Customizer and will continue down the page.

The Solution

This is a debug message caused by PHP 5.4 on your server and does not indicate a functionality problem with the customizer in most cases. By default, PHP has this set to 0 for production servers on most hosts  (your host should have PHP debugging turned OFF)

Unfortunately, shared hosts always have display_errors on. To turn this off yourself, you can attempt to modify your WordPress config.

  1. Connect to your server via FTP
  2. Download a copy of the  wp-config.php and open it in a text or HTML editor
  3. Find the following section and ensure WP_DEBUG is false: 
    /**
* For developers: WordPress debugging mode.
*
* Change this to true to enable the display of notices during development.
* It is strongly recommended that plugin and theme developers use WP_DEBUG
* in their development environments.
*/

define('WP_DEBUG', false);
  4. 4. Paste the following line right below the WP_DEBUG line: 
    ini_set( 'display_errors', 0 );
  5. Save and re-upload the file to your root directory or wherever WordPress is installed.

If this does not work, you will need to contact your host about disabling PHP debugging/error display for your site.