wp-content issue

For security reason (as suggested by Better WP Security plugin), I changed the default wp-content name. Everything seems working correctly. But on my 404 error logs, it show warning:

==============================
URI:
/wp-content/plugins/slick-contact-forms/css/admin.css
Referrer:
http://www.mysitename.com/wp-login.php
==============================

Hope the next release of this plugin will fix this issue. I found this information, perhaps it helps:
http://codex.ww.wp.xz.cn/Editing_wp-config.php#Moving_wp-content_folder

http://ww.wp.xz.cn/extend/plugins/slick-contact-forms/