Playing Heroes of Might and Magic V on Ubisoft servers.

Most likely, you have the silver edition of the game (in which case, patch 1.6 cannot be installed; you need to download 1.5). I recommend downloading the 1.6 cumulative patch in that case.
It installs on the silver edition without any problems and also on any version from 1.0 to 1.5.

Thank you for the link; it worked!
And what does "silver edition" mean? Is it some kind of inferior version...?

And another question:
How do I navigate the online menu of the game? I don't understand how to join a game... What is a "profile," and I don't understand where to create it.