Problem with content – not loading

Question

The error message you get means that a function has been hooked without a valid callback.

In other words it means that somewhere in your theme or in a plugin a function has been set but it’s not “hooked” properly. See the example :

function add_post_content()  //<- the callback
{
// blabla
}
add_action( 'hook_name', 'wrong_name_function' );//<- hooked in WP

So ‘wrong_name_function’ has to be replaced with ‘add_post_content’.