I had the same issue and think I just figured it out for myself.
Open Premiere Pro CC 2014 and create a New Project. Then go to Preferences and Select Audio. At the bottom of the window you should see a button for Audio Plug-In Manager.
Image may be NSFW.
Clik here to view.
When you open the window do you see anything listed in the box for Available Plug-Ins? If not click "Scan for Plug-Ins". Once it scans, any plug-ins it finds will be added to the list like so:
Image may be NSFW.
Clik here to view.
This was happening to me after re-installing my copy of Premiere Pro CC 2014. When I opened up my previous version of Premiere Pro CC and navigated to the plug-in box, they were all there. But when I opened a brand new project in CC 2014, the list was empty. I had to tell Premiere to find them all again. All of the AU plugins are native to Final Cut Pro, not Premiere (they all have "Apple" in front of their path name), hence why they weren't there when I re-installed.
I hope this helps.
I used this forum question to help figure the issue out. Maybe you'll find some additional information about your problem here as well: Re: Audio filters unavailable?
