[Steven Zahm]

@ Bob

Seems you or web host has the server setup to show PHP notices. This is not a good practice for production servers. Errors and notices should be logged to a file outside of the public_html directory so it is not publically browsable.

In this instance it is showing a harmless notice for devs so they know a function has been deprecated so they can plan on removing its use at a later date.

This WordPress doc page explains more about PHP warning and notices:
http://codex.wordpress.org/Debugging_in_WordPress#PHP_Errors.2C_Warnings_and_Notices

What you need to do is add the following to the wp-config.php file:

define('WP_DEBUG', false);
define('WP_DEBUG_LOG', false);
define('WP_DEBUG_DISPLAY', false);

That should fix it up.