It's reporting as "missing on our servers" probably because there is a later version of the article which doesn't include it, and that has been deleted for some reason.
However, it's possible that the Admins can find you a copy in their archives / backups if you ask them nicely!
Ask them if they would be so kind here: Bugs and Suggestions - CodeProject
] and see what they can do. Have a little patience though, they are based in Canada, so they won't be in the office for quite a few hours yet.