You are putting <link
rel='stylesheet' id='datatables-demo-css' href='http://www.datatables.net/release-datatables/media/css/demo_table.css?ver=3.2-bleeding' type='text/css' media='all' /> in the head of frontend. Why? You probably need it just on one specific page of admin, not full admin and not frontend
should be at least
add_action( 'admin_init', 'my_plugin_admin_init' );
function my_plugin_admin_init() {
wp_register_style( 'datatables', WP_PLUGIN_URL . '/yourPlugin/datatables.css' );
}
(or with some check of a page)
or you can simply add the css load to body of that page where you need it (it works even when it is not in head)
http://wordpress.org/extend/plugins/contact-form-7-to-database-extension/
