Question. How do I run the launcher as an administrator?

Right-click on the launcher in the file explorer -> run as administrator

Lider1, regarding the last two crashes.
One occurred when the second player joined, and the other when receiving a map from the host. Both crashes were due to an invalid value in a specific field (different for each crash) of the New Scenario Manager structure (does that sound familiar?).
I don't know why these fields had invalid values. HD shouldn't be touching anything there. I don't know what these fields are for in the game, and there's no reason for me to touch them, as I don't understand what they do.

HD does, however, modify the New Scenario Manager structure in places, adding new interface elements, setting previously saved random map settings, fixing desynchronization, and changing alliances. And, theoretically, my mistake here could be the cause of your crashes. Or there might be a conflict with GameRanger, as it also seems to patch the game. But why does the error only appear for you??

In the next version, I'll make options to disable setting saved random map settings, fixing desynchronization, and setting alliances. You can then try playing without these features.