certain titles not mounting anymore. picture included

i have age of chivalry, and dystopia installed, games that usually would mount right on to garrys mod, and were working fine a week ago. however they are no longer mounting, although counter strike source in mounting just fine. here is a picture of what i am seeing. as you can tell, the games i dont have are marked with an X. the games i have installed, but arent mounting are marked with a picture of a file, and a red circle. like age of chivalry. how can i solve this? (i have tried all the basic methods of troubleshooting. uninstalling all of them, and reinstalling Etc.)

http://i.imgur.com/u32Ir13.jpg?1

All those games cannot be mounted because the developers have not updated to Valve’s new content system. Not a problem with Garry’s Mod.

does this mean those games are no longer compatible? and will never mount again?

Until their developers decide to update their games.