Same here. Downloaded 2 times with corrupted "setup_kings_bounty-2.bin" file.

Check to make sure that you anti virus or firewall are not interfering with the download. Also if you have a bit torrent style download on the go at the same time as a normal one I think sometimes It can cause problems.
Other then that you could contact gog support about it.

There's the same on Windows XP Pro. It's not related to the OS.
There's an error in one or more of the files. In "setup_kings_bounty-2.bin" as mentioned previously, in the executable or in both of them.
I'm going to contact GOG.com's support.
P.S.: I just sent them a message. I hope we'll have a solution soon.

After trying to install the game without checking the files integrity, all the time I got an error message informing, that c:\Program Files\GOG.com\Kings Bounty\sessions\base\locations\tex_darion_4.stream is corrupted. It looks like it is not an antivirus fault at all, but game itself.

Try using their downloader or a different client? It worked for me using Firefox on Windows 7 x64 (with av/fw).

Same problem here. Tried both with downloader and browser. Tried using Chrome, Explore and Firefox. Disabled both firewall and anti virus. closed all my unnecessary applications. Same message.
Skip the integrity check, worked for me.
Scratch that, game just crashed.

I've tried using Firefox (been using Chrome before), disabling every possible thing that could interfere still no luck.
Skipping the check didn't help either.
Any word from support?

A quick Google search revealed some Russians with the same problem, unfortunaly... its in Russian.

Not yet.
You should never skip integrity check for downloaded files not only in order to ensure a valid installation, but for security reasons too.
Friend nicolaierdk you could try Google Chrome's translation tool, specifically if a precise translation isn't necessary. I recently used it to read a text in German. Translation to Greek was full of errors, but to English was good enough.

Questions were asked but not answered, dammit!

Sadly, I have encountered the same error on W7 32. Game downloaded by GOG Downloader.

I say; TO THE MYSTERY MACHINE!

Is support sleeping?

im on win 7 64bit. Downloaded using gog downloader.Same problem. :(