Colorbox ajax loading of outside HTML content works perfect on localhost but not on server

You should not load wp-blog-header.php yourself.

Use wp-admin/admin-ajax.php instead, as described here:

http://codex.wordpress.org/AJAX_in_Plugins

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)