OK, I'm getting the same error. I haven't played Sins-Rebellion (SR) for a few weeks now. However I have several friends who have, and something like a week or so ago they had the exact same issue as the above with one exception.
The game failed to launch.
The windows pop-up asks if steam can make changes, followed by performing first time set-up. Their STEAM status shows they are playing SR, and then revers to simply "online" and the game never launches.
They were able to resolve this issue through uninstalling and re-installing their copy of SR. I tried the same, but to no avail. Verifying my local files produced one file unable to be verified, and it'll be downloaded and replaced. Still nothing.
I find this thread, follow the directions regarding the C++ thingy (I have no clue about coding, so I'm just following the above instructions, praying that it'll work.) When I tried to run the game, it did the C++ installer package window, and then went silent as is the norm come today. I tried to run the game again, in hopes that the installation interrupted the normal game launch routine.
NO. Frakking. Joy.
NOTHING has changed in regards to my computer from two weeks ago through today. Not a thing. And yet, I can't launch this game anymore. One of my friends experienced it in the space of less than an hour. He was playing the game, shut it off, then came back to play it again about an hour or two later and found it wouldn't launch. he re-installed and it worked. I re-installed, patched, validated, did this C++ thing, and still nothing. And this is the *ONLY* thread I can find, ANYWHERE, dealing with anything this type of problem.