Attachment links not working. Please help

Hello. I face problem with my attachment links google put all the attachment links to 404. URl contains %2F with it. Is there any bug in urls please give your suggestion to overcome this issue.

URL’s looks like this:

http://example.com/?attachment_id=82%2F

Is this Yoast tralling slash problem or any other.
Thank You.

http://wordpress.org/extend/plugins/wordpress-seo/