I say that it is corrupted cause i had this problem myself. No matter what i tried nothign had worked.
I tried to just replace the dll another error came up. I tried to replace that one another one.
In the end i re-downloaded it cause it was just easier than replaceing 3/4 of the dll's that were giving me errors.
I see you got it from the Office site when they offered it to the public. That is the same one that gave me a issue. I ended up downloaded the .exe from the Beta site. Worked much easier.