A search for that dll didn't bring up any results which is unusual - are you sure you spelt it correctly?
There's two options here, firstly the dll file is a core windows DLL that's become corrupted, in which case you'll need to do a repair install of windows.
However, the more likely option I think if that's really the dll name is that it's become infected with some kind of virus and you'll need to get rid of it. So I'd download spybot s&d, run it in safe mode and see what it comes up with - if it doesn't find any problems then we can take it from there.