Same problem here. As a result add-ons wil not install !!!
Please can you send a screenshot and also confirm that you have not upgraded to PS CC 2015?
I have upgraded to PS CC 2015. And as you can see in the screenshot, only Illustrator CC 2015 and Indesign CC 2015 are shown among the products. But non of the other CC 2015 products like Photoshop.
And it is impossible to install interactive luminosity mask (compatible with PS CC 2015) via the exchange function in the extension manager...
Regarding the 'Interactive Luminosity Mask' extension you can install it via the Adobe exchange: https://creative.adobe.com/addons/products/12307
If that does not work (which it should), you can download and it and install manually: Interactive Luminosity Masks - Sven Stork
If nothing else works for you let me know (I am the author of the extension), I'll see how I can help you.