I am personally out of Ideas, as it would seem to not follow the logical coarse on how these files are found. And being that you are the only one at this time experiencing this issue.
Normally if something is needed like that, it looks at the present folder, then if it cant find it there, it is supposed to check the windows system folders, then thro an error if it cant find. your install seems to think it cant find what it needs, or may not have proper permissions to do such a thing. But as you can install other games and play them, it is really baffle ling as those games have the runtime distributions of the same files, we had you install this morning.
I am going to have to pass this to the programmers, and let them figure it out. I am out of options my self.
This install apparently says its fine, but the actual running of the game says no way.
ok, one more thing just popped into mind. Can you go off line on steam, and then try to run GG again. Maybe forcing to run in admin mode might kick it into happening.
I know, more hoop jumping, and again I am sorry.
Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz, 2400 Mhz, 4 Core(s), 4 Logical Processor(s), 8gb RAM, Nvidia gtx660, Windows 7 Pro 64bit