Exact error/ warning?
The last version supported by CS5 is Camera Raw 6.7.1. You can download and install it manually.
If you need more recent, you should upgrade CS, use Lightroom, or use the free DNG Converter (8.4 is the latest official release).
All is explained here: http://yphotography.co.uk/articles/get-adobe-camera-raw-acr-open-photos/