After numerous downloads (5 precisely; 4 "normal" 1 with downloader) all I get is a corrupted "setup_kings_bounty-2.bin" file.
I'm on windows 7.
Any ideas?

There's an error in one or more of the files. It doesn't make sense to download them again and again using different methods.
We have to wait for a solution by the GOG.com's support team.
I sent them this message:
Maybe they'll post a solution here. If they just answer to me, I'll post the message here as soon as possible.
You may contact them too if you like.

But how comethat corrupted file (which have no name in my heart from now on) works for 98% of the people?

Same problem. I have Windows 7 64 bit and tried both Firefox and GOG Downloader.
Probably they use more than one server and the game image is only corrupt on a subset of the servers. This is corroborated by the fact that the problem only seems to concern people in Europe.

I would, if it would work.
And thanks for adding your invaluable input (the game is working for YOU) to the thread!

Don't expect a reply earlier than on Monday, maybe tomorrow. MAYBE
They usually reply within 2 business days
BTW just in case: I have bought it too and I have the same error.
EDIT: epic fail on my side

English is clearly not your first language. The person you're responding to here got the impression that the game worked for you and that you were trolling (it obviously isn't working for him, either: "i care it to work for me"). I initially also had the impression that you were trolling. However, I then noticed that you were, in fact, the topic starter and that the "point" of your message was apparently to satisfy the need to contribute some arbitrary statistics, which actually contribute nothing to the discussion on hand (unless you have the proof to back up the claim that the game works for 98% of GOG.com users).
As regards the topic, I bought the game but I'm not downloading it yet until the GOG.com staff have solved whatever it is that causes the problem.
Edit: stupid tags.

Yep, same error here too. Wonder what's going on here...

Same error ...
Windows 7 Ultimate 64bit.
Downloaded using both the downloader and browser several times.

Same problem... win7
corrupted file: setup_kings_bounty-2.bin
filesize: 1 228 139 465 b
md5 hash: B94511B576F82DBE584EABB46B3B47C1
server: wpc.11df.edgecastcdn.net

Same here; second bin file is corrupt, with check skipped it says that something along the lines of tex_darian_4.stream is corrupt.
I have the worst kind of luck with these things. I bought Mount&Blade:Warband as soon as it became available from the TaleWorlds site, and the version of the file on their site at that time turned out to be broken.

Still no response from GOG Team?

For what it's worth: My first download of the bin-2-file was corrupt too. Downloaded it a second time (using the browser) and it worked.
Either GOG ninja-fixed this or I was just lucky.

Redownloading now , hope your right and they fixed it

Nope. Just downloaded, still corrupt.