When I try and open the updater I get a message saying the configuration is incorrect and to try reinstalling. I redownloaded and reinstalled it and it's exactly the same.

I'm also having this problem, although still 24 days till next update so maybe it'll work once there's actual updating to do :/

Well, I've reported it on the game's official forum so at least they should be aware of the problem now.

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.

Note:
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 :)

I also have a problem with the autoupdater, and I'm running windows 7. Right clicking to run as administrator doesn't work either. I get an error message and the update fails.

So apparently I did guess wrong assuming it is a XP-only problem .
Well anyway a trial on 2 x 7 and to 2 x XP is not a exactly a statistic material..

Mayby this info can help:
My win 7 install is with UAC (User Account Control) completely disabled.
Also I install my program ( including don't stave) well away from "C:\Program Files" or "c:\Program Files (x86)". Partly because they can give give compatibility problems with older stuff. (for more info see note below).
I did not expect this to matter for a new game like don't starve though.

Running in FULL screen on XP is posible (I did it anyway):
1) go to ...\Documents\Klei\DoNotStarve
2) open settings.ini
3) under the [graphics] section add the lines
fullscreen_width = 1680
fullscreen_height = 1050
change tho numbers so it is identical to your full screen resolution
4) change the line
fullscreen = false
to
fullscreen = true

note
window vista and later do some (for retro gamers) real annoying stuff with security permissions within the default program folders. Done to give higher security against hackers and virus,
If one don't care about that security. It is possible to just take ownership and then change the permissions to a more moderate level. But please do not do this at home (exept if you are a geek and really know where your towel is).
A more safe solution is to always install to a different install patch than the default like c:\games or d:\MyOldStuff etc

Still have the configuration is incorrect error after applying the patch on XP.

tbh I don't even know what the updater is, there was 1 patch file when I downloaded the game and that's it I just run the game and click stuff :S is there a seperate updater?

Same here (Win XP); Solution appreciated.

@bokkafa: There's a small program ...\Don't Starve\updater\16\updater.exe which apparently is the updater. I don't know how or if it works as an auto-updater which is triggered automatically. At least it doesn't look like in my case, because my firewall logs no connection attempt by dontstarve.exe nor by updater.exe.

That worked great, thanks.

cheers dude would definitely not have found it otherwise lol seriously though I wish there was a clear link to it or something :D

The workaround worked fine! Thanks

Excellent! I was having the same error message as the OP on my Windows XP machine (but not on my Win7, curiously).

Workaround worked a treat! Game on!