You are copying the permalink displayed to them by their wordpress blog.

This is not the normal permalink, it is just a shortened version for display purposes so you can see how it ends too

For example, we have a rather long URL in our blog

When you edit the post, you get the following as the displayed permalink on the dashboard:

But it is not the correct one as wordpress just makes sure to fit as much as it can without omitting the end

The normal URL is : http://blog.inlinkz.com/2014/04/about-the-heartbleed-internet-wide-security-bug-and-how-it-affects-inlinkz-and-other-services/ (which is quite big).

You should grab their permalink by copying from your address bar rather than your wordpress dashboard.

So, in the wordpress dashboard, you should "view post" and then, grab the URL from your own browser address bar (and then, paste this to the respective InLinkz box)