Hi there, I had the same problem with this DLL. Upgrading from VLC 0.8.4a to 0.8.5. I found out that it is for win9x/ME OS. And on checking my Windows>System folder, I found I didnt have it. So here is what I did.
1) I went to
http://www.dll-files.com/
2) Searched for unicows on the left hand side search box.
3) Downloaded and extracted the file into Windows>System folder.
4) VLC 0.8.5 worked after that.
Just an after thought: I didnt have the unicows.dll at all so when I put it in the system folder, I wasnt overwriting an existing DLL file. I would perhaps recommend searching for the unicows.dll file first in the system folder (Incase it is there but corrupt). Then copy it to somewhere safe and then extract the new one into the folder.
If you have the know-how, backup the registry first. But my experience as described above was immediate and painless.