The only thing I can suggest right now is that you may have the show hidden files option disabled in your Folder Options. Go into your Control Panel, open Folder Options, and then see if "Show hidden files and folders" isn't checked. If it's not checked, then check it, save the settings and see if the file appears.
When working in the system folders you might also have to uncheck the box "Hide protected Operating system files (Recommended)"
However:
Also, one more thing to note: I really wouldn't recommend getting DLL files from third-party sources, if that's where you obtained said DLL from. Not only could it possibly contain viruses/malware, but it could also corrupt other functions with your system.
I agree 110%
As far as I know System32 is owned by TrustedInstaller. So even as administrator you don't have the neccessary right to change things in it. That's mostly in order to keep the system running; the only way you can change something is changing the rights properly, which can cause your system to take major damage to a point where you have to reinstall the whole thing.
The Administrator account can make changes to anything. On my installation of Windows 8.1 Pro, I show that "SYSTEM" is the owner of files in the System32 folder.
I really need a new signature.