Well, at least I fixed the add media button

Well.. This post did most of the actual thinking for me ..

WordPress add media fix

Basically you need to open your “wp-config.php” file in the root of your WordPress Install.
Search for this line:

require_once(ABSPATH . ‘wp-settings.php’);

And just before it add this code:

define(‘CONCATENATE_SCRIPTS’, false );

Now your WordPress Install should be fixed!