Didn't work. Also, launching the installer from the GOG downloader doesn't work. It tries to open a .bin file with notepad for some reason... So I launch the installer with the executable in there. Could that have something to do with it?

I have a weird problem. After i registered the game, I tried to register the game in another user account of the same PC. But the launcher just gives me some weird empty and useless error message.

If i enter a made up username or wrong password, the error box tells me so, but if i write everything correctly i just get that...

I think it may be related to my copy already being registered in one account but i can't be sure since i just get that useless error notice.
Does this mean i can only play in one account at a time, and i have to void the registration in the first one to be able to register in the other?

I have a problem with the registration. I have the GOG version of the game. The game works fine, but when i try to register nothing happen. I can´t enter with my account and can´t even create a new account. When i try to obtain my password of my account (maybe i was entering a wrong password or simply i forgot) the launcher show me a bugging "OK" dialog box and nothing arrives to my mailbox. Somebody with a similar problem?

No that has nothing to do with it. The Downloader just seems open the wrong file the .bin file is a image file. On my end it wanted VLC to open it. But you just have to run the .exe from the GOG download folder, and you will be fine.