As mentioned in the link, there will be a fix for that "problem":
http://www.gog.com/en/forum/the_witcher_2/the_witcher_2_patch_1_1/post266

Long have I waited to finally get the Patch with the promised aspect ratio fixes.

However: how do I know that I've 1.3 properly applied?

Look at http://en.thewitcher.com/patch1-3/ is just utter confusing. I've the gog version. I just installed it. I runt the included patcher.exe and it says the game is up to date.

I downloaded The_Witcher_2_Patch_1_3 and when I run it I get "Installed game version is invalid or incomplete".

So I guess I've to assume I've the latest version?

This is how the settings are: http://my-serve.rs/tmp/the_witcher_2_settings.png

But in-game, I still have the black bars (the reason I waited for the patch so they're finally removed): http://my-serve.rs/tmp/the_witcher_2_still_black_bars.png

I've then gone to my Documents folder and removed the "Witcher 2" folder completely, just in case I'd have left overs which may not work. When I now launch the launcher, I get a empty message box every ten seconds: http://my-serve.rs/tmp/the_witcher_2_launcher_problem.png , including a message about refused connections

Any idea what I'm doing wrong?

thx

You can just check the file version of witcher2.exe in the \bin folder. If it says 1.3.x you have the current version.

Thanks, that helped. It was version 1.0.something. I realized that I needed to go to gog.com and download The_Witcher_2_patcher_1.0g-1.3 and install it.

Easiest way is to download the new autopatcher from your account.

It will tell you what version you have, and if there's any patches available.