|Try running sfc /scannow (note the single space after sfc).|
If this doesn't help you should be able to copy across an up-to-date copy from:
It's location is given in reply #1.
Afterthought. Are you trying to register this dll using regsvr32?. If so this is a completely different story (and not all dll's can be registered). In which case the file will already exist in its correct location. If you are not trying to register a dll then please let us know the background to this problem and exactly when this error appears.
Long Range Golfer