Emailed Author: Your plugin calls CSS via links: <link rel="stylesheet" id="wp-admin-css" href="' . $css . '" type="text/css" media="all" />
You should be using wp_enqueue_style() instead.
Please review http://codex.wordpress.org/Function_Reference/wp_enqueue_style and update your plugin accordingly.
When you've corrected your code, reply to this email with the updated code attached, or provide a link to the new code.