RunDLL won't stop popping up

I just installed win8. Everything was fine before this, and is now. But now, this dialogue box keeps popping up in the foreground of my windows - Meaning that I've had to minimize it about 10 times just writing this paragraph. Clicking OK does nothing and just brings it up again:

This is its icon:

I hate to say it, but this looks like a system compromize. Checking Bing for "shim64 dll error on Windows 8" turns up tons of posts that all involve this filename... except that the directory and the suffix of the filename (_chvuub in your case) are always different sequences of apparently random letters - a classic virus/malware tactic to hinder identification. I strongly recommend a system scan and - if easy - a complete reinstall of Windows 8 from a fresh, trusted source.