media uploader isnt working

Hey,

I have a problem. The media uploader in the Admin section isnt working anymore. I use a custom made theme.
When I activate Twentyeleven theme it works.
When I remove the jquery_latest function (see code below) in my custom theme is also works.
But then my jquery scripts in de frontend don’t work anymore.
How can I solve this?

function jquery_latest() {
    wp_deregister_script( 'jquery' );
    wp_register_script( 'jquery', 'https://code.jquery.com/jquery-latest.js');
    wp_enqueue_script( 'jquery' );
}
add_action('init', 'jquery_latest');