Hi ELFswe,

I have been getting the exact same error. So far I have only ever seen it happen during the installation of GOG games. It seems random wether it happens or not. When it does happen it always happens just before a game is finished installing. Also on some games I get an additional error message that simply says "Invalid Opcode". The most recent example of a game that has both error messages is "Don't Starve".

I know my installers are good since I download them directly to a Btrfs filesystem which is resilent to file corruption. If the GOG downloader has no issues with the installer once it is on that filesystem then it is pretty much guarenteed to be error free. I can confirm this by running a scrub on the filesystem which checks the file and I have also compared the "Don't Starve" installer MD5 sum with one from this forum. So I have ruled out corrupted installer.

I have UAC turned off and always right click installers and run as administrator. I have the latest Avast and Malwarebytes and have disabled both. I have also tried running the installer in compatibility mode (XP SP2 as suggested by the troubleshooter). I have tried all these options at the same time and the errors still occur.

This is on a clean install of Windows 7 64-bit which is only about 2 weeks old. I first noticed the issues when I was trying Windows 8.1. On Windows 8.1, the 1st error would occur on what seemed like every single GOG installer. The 2nd error "Invalid Opcode" would only occur on certain installers (for example at the time I was getting it with "Sid Meier's Covert Action". Just tried it replicate the error on Windows 7 64-bit and with 4 installs, not one error...

I have installed a lot of GOG games recently, but "Don't Starve" is the first game which is showing the same error now that I'm back on Windows 7 64-bit. I have re-installed the game multiple times and the errors only occur about half the time.

Also I have run memtest86+, memtest86, Windows memory diagnostic and prime95. Apart from some issues with my new graphics card (Radeon 290), my system seems stable.

Anyway, initially I thought there might be something uniquely wrong with my Windows 8.1 install since it affected every GOG installer. But now I've seen at least one other installer doing this under Windows 7 64-bit. So after seeing your post I thought I better let you know that whatever is causing this problem, probably is not solved by simply redownloading the installers (you may still have the underlying issue). I have not experienced problems with any other installers or software, so maybe it is some sort of compatibility problem with these particular Inno Setup installers?

Yeah, I'm also getting the opcode error after the first error message.

I am getting that error on every gog installer. It's weird. I never used to get these errors on vanilla windows 8. I guess it's a windows 8.1 issue?

Yeah probably. When I was using Windows 8.1 about 2-3 weeks ago, every GOG installer I tried had the error. All my GOG installers are also up-to-date since I just downloaded them all within the last 3 weeks.

Hi Gowor,

I was not able to replicate my issue with "Don't Starve" again under Windows 7 64-bit. I also tried to replicate ELFswe's issue by installing "Shadow Warrior (2013)" numerous times. For whatever reason these and all other GOG installers are no longer showing any errors under Windows 7 64-bit. I also don't have the install logs anymore because ccleaner wipes my temp directory.

So I have done a clean install of Windows 8.1 64-bit with network cable disconnected so it cannot update. GOG installers work fine.

Plugged network cable back in and installed 1st batch of Windows updates. GOG installers still work.

Installed 2nd batch of updates. GOG installers still work. Still working after all updates installed. Even after installing directx.

So I moved on to installing drivers. For some reason as soon as I installed the AMD display driver, the GOG installers have both of the weird errors again. I have tried the latest stable Catalyst 14.9 and latest beta Catalyst 14.9.1. Problem exists in both. For these errors to occur, only the display driver needs to be installed. Installing Catalyst Control Center, HDMI audio driver, etc, does not cause the error.

Games tested were "Sid Meier's Covert Action" and "Don't Starve".

I will have to attempt to send you the install logs and dxdiag another way since it complains about wrong file type if I try to upload txt or zip files.

Is there actually a way to send the install logs as txt files? The support page does not let me attach txt or zip and states only images can be attached :S

So as of right now I am running a new clean install of Windows 8.1 64-bit that I installed just hours ago.

-UAC is off
-It is fully updated.
-directx9 has been updated with offline and web installer
-For testing purposes I have not even installed any antivirus and have disabled Windows Defender
-sfc /scannow reports no problems

So from this point:

-if I have the latest AMD display drivers installed, then I will get the errors during install
-if I uninstall the AMD display drivers, then the installers work without errors

I have already PM'd Gowor these files, but in case anyone else wants to see:

dxdiag:
http://pastebin.com/cw4yVpK5

Install log:
http://pastebin.com/vyVRGrsS

The Windows System File Checker tool also did not find any corrupted system files:

C:\Windows\system32>sfc /scannow

Beginning system scan. This process will take some time.

Beginning verification phase of system scan.
Verification 100% complete.

Windows Resource Protection did not find any integrity violations.

"Cannon Fodder" is one of the games that does not get the 2nd error "Invalid Opcode".

The 1st error is slightly different too, which may explain why:

------------------------------------------------------------------------------
Internal error: Expression error 'Runtime Error (at 16:21):
Invalid floating point operation.'
------------------------------------------------------------------------------

as opposed to:

------------------------------------------------------------------------------
Internal error: Expression error 'Runtime Error (at 18:21):
Invalid floating point operation.'
------------------------------------------------------------------------------

Install log:
http://pastebin.com/7LFCMcCD

Got the error now again, but this time with Aliens vs Predator Classic 2000.
Not sure if it's needed, but I got you both the 32-bit and 64-bit log for DxDiag.

DxDiag 32-bit:
http://pastebin.com/PR0ZbCKG

DxDiag 64-bit:
http://pastebin.com/AqeXy1Cg

Install log:
http://pastebin.com/f4We0ae4

EDIT:
I just started AVP Classic 2000 and got the message again when the Galaxy installer almost were done.
I copied just the lines were the error occurs.

----------------------------------------------------------------------
2014-10-20 21:52:32.492 -- Icon entry --
2014-10-20 21:52:32.492 Dest filename: C:\ProgramData\Microsoft\Windows\Start Menu\Programs\GOG.com\AvP Classic\Aliens vs Predator Classic 2000.lnk
2014-10-20 21:52:32.493 Creating the icon.
2014-10-20 21:52:32.520 Successfully created the icon.
2014-10-20 21:52:32.547 Exception message:
2014-10-20 21:52:32.547 Message box (OK):
Internal error: Expression error 'Runtime Error (at 23:21):

Invalid floating point operation.'
2014-10-20 21:53:09.348 User chose OK.
----------------------------------------------------------------------

Is there a fix for this yet?

I'm having the same issue with The Witcher 2

I guess it's a super rare bug since there are hardly any of us reporting this.

You wouldn't happen to be using a Radeon R9 290 graphics card would you? I recently bought a Radeon R9 290 and ever since then I have been getting the problem. It seemed to be faulty (random BSODs and driver restarts, but apart from that was working great and getting good frame rate) so I have claimed warranty on it and gone back to using my old Radeon 5870. I have not seen the error messages again since.

When I was still using the Radeon R9 290, I could always make the problem go away by uninstalling the display driver. What this has to do with GOG's installers I don't know. But for me, it worked ever single time when I was testing. Not that it's a viable solution, since we kind of want the display driver installed to play the games lol.