Yoast SEO breaking media upload

You have introduced 2 additional problems by adding the jQuery from Google CDN.

1. The admin interface needs jQuery called in no conflict mode so it won’t interfere with the other scripts WordPress uses for the dashboard.
2. The WordPress dashboard is not yet compatible with jQuery 1.5 thats why it was pulled from trunk right before 3.1 was released.

See: WordPress Development Blog.

If you want to use Google’s jQuery register it like this:

function my_init_method() {
    if (!is_admin()) {
        
     wp_deregister_script( 'jquery' );
    wp_register_script( 'jquery', 'http://ajax.googleapis.com/ajax/libs/jquery/1.5/jquery.min.js');
    wp_enqueue_script( 'jquery' );

    }
}
add_action('init', 'my_init_method');

Also your using DDSlider and Magic gallery and both use timthumb.php which can cause problems with the default WordPress media functions.

ThemeForest plugins and themes are well known to screw with anything having to do with jQuery even after deactivation.

Almost all Themeforest plugins and themes add their own jQuery via script tags.

I would suggest first removing your enqueue script or change it not to use it in the admin then use Firebug and find out where the breakpoint point is.

Make sure your browsers cache is cleared after you disable any of the plugins for testing.

Another thing you can try is disabling the Ajax meta descriptions in the Yoast plugin and see if that makes a difference.