You might want to try to remove Reality ( delete the whole Reality subdirectory inside addons ) and try again, this time logged in as the Administrator of the machine. Other people reported this operation as being the solution.

Hope this helps.

Paolo

https://www.preta3d.com
FB: https://www.facebook.com/RealityPlugIn
Tw: @preta3d
G+: https://plus.google.com/106625816153304163119
The Reality Gallery: https://reality-plug-in.deviantart.com