HoMM3 HD is a mod (add-on) for the game Heroes of Might and Magic 3.

to be honest, I never figured out how to launch any of the betas :o

You have an empty list of executables. This means you either installed it in an empty folder or the executable is not usable.

Added after 42 minutes

...Should I create a collection of videos and saves showing where this happened (with a description of the settings) or wait for the full 3rd part?

This bug, where a '1' is added, can only be caught by recording the exact sequence of actions that causes it to occur. This is the most useful information.