Hi, ErgoProxy,
Let's try something out that could be a potential resolution for your problem. This I'm not sure if it's going to work 100 % but there's no harm in trying out the fix. Firstly, go for what duckbenok suggested and download and use a different de-compressor like WinZip and it has to be compatible with the OS you use if it's x86 or x64. Secondly, re-download blackout ro files and make sure it was downloaded correctly to secure a clean copy and confirm that it is not a corrupted file issue. Thirdly, last and a resolution I think you should try is to download and install Visual C++ compiler packages. Those packages are VC9, VC10, VC11, VC13 and VC14. The logic why I asked you to download the Visual C++ compiler packages is because in most cases or almost all cases, games and programs that are built using MVS(Microsoft Visual Studio) require those. Make sure and be certain that what you download is going to be compatible with the OS you are using if it's x86 or x64.
Again, this last suggestion is something I personally haven't tried and is only based from what I understand because I personally had not encountered an issue like yours so I am not 100 % certain if that will contribute to the fix but hopefully, this helps.
Edit: Another option would be to check your security software if it prevents blackout ro files from being extracted.