In doing seo optimization, one of the parameters that must be considered is the status of the link in the blog must be active (healthy), in the sense that there is a link in the blog actually refers to a page that is still active, if the link in your blog refers to a page that was deleted or to a page that is forbidden by the google robot, link on your blog is considered a dead link (link error) by google. The more dead links (broken link), the more likely you are experiencing a penalty blog from google. Increasingly difficult to raise the page rank.
You need to test / check the status of links on a regular basis, so you can minimize the error link in your blog.
There is one facility that allows you to check the status of links in your blog, please open the site link validator