Plugin compatibility question.

I am trying to move from ProTools to Audition for certain post projects.  All of my VST/VST3 plugins are showing up in Audition when I try to add them to a track.  However, some specific plugins show in the list but don't load when I select them.  Specifically, NX Virtual Mix Room, Dourrough Meters and  any of the Waves Abbey Road plugins.  Is that an issue with these specific plugins, or is there something I need to set in my Audition settings that is preventing them from loading?  All other Waves plugins load properly.  The thing that is baffling is that they are showing up as installed but when I select them they don't load.  Any suggestions?

Thanks!