digital camera RAW compatibility update problem

I recently updated to the digital camera RAW compatibility update version 6.21. It has added this update 2 days prior to today and now i can not install it at all. The update keeps showing up that it needs to be done but i can't do the install and the update will not go away. How do i fix the problem within the app store. I am concerned especially with the SIerra update next week that it could cause a problem