Audition CC will not scan for VSTs even in default folder

I cannot get Audition's plugin manager to scan for any plugins. It does not matter if I type in the folder where the .dll is, or if I put the .dll in the default folder and try there. I have tried with various 64 bit VSTs. Nothing. The scanning window flashes, but never moves past 0%. Should I give up? I'm trying to use and learn on Audition, including using lesson files, which require the VST loading. Any further suggestions? I am running Win7 64 bit. The VSTs work on another Windows 64 bit DAW.