This I a WINDOWS XP bug.
installed it on windows 7 - no problems.
I noticed the fact, that the autoupdater is neded, as it realy do some updates on top of the GOG distibuted file.
I have 3 computers all is set up so I can boot to 7 or XP on demand. so can test this.
I tried installing it on XP next and now the autoupdater did not work.
The message is as k1ttenface stated a statement asking to reinstall because of incorect configuration.
tried it once more on xp on diferent computer... Same result.
Tried on 7 on that 2nd pc, where it worked, So I think this one is OS dependent.
I think this one is a problem that only exist for GOG versions of the game.
Because (if I am correct) other users get updates it a diferent way. Like direct tru steam or tru humblebundle.
I have NOT isued a suport ticket to GOG-support, NOR have I register at the oficial forum and "whined" about it there.
For me this is not a big isue I can just update using 7. But some XP-only users migth regard this a bit more seriosly.
Ah, good to know. I'm an XP user too, which also means I can't get fullscreen. :(
Still loving the game though, trying to figure out which character is my favourite :)