I am having the same trouble. I don't have a button to download camera raw and my photos are just openeding up and I can't edit them in RAW. I have windows. The list on the opening box had Camera Raw listed under Photoshop and Lightroom, but there is no button to push to open it up.
I had been just using Lightroom for the last months, and now I wanted to use Photoshop, and can't.