I think this one is user error where I have a setting etc messed up:  I can access my plugins on the master bus only.  If I choose a regular track, right click on the fx panel only a small amount of plugins (the ones that come with Sonar are available.  If I choose the master track and right click on the fx panel, I can choose my waves, steven slate etc plugins.
 
Also if I run the plugin manager it stops responding.  

 

 

the "stopped working" dialog shows a steven slate plug as the problem - try renaming it (to something other than .dll so it's ignored by the scan) or moving it and then rescanning? hth

It's not the scanner that's failing, but rather the FG-X plugin. You might try uninstalling and re-installing the Slate stuff. There could be some helpful information in the crash dialog that's not visible in your screenshot, like the exception class.

Mine is now crashing in 32bit X3 when it hits Melodyne. Remove Melodyne from the search and it crashes on Guitar Rig5. 64bit X3 works as intended.
 
Do I need to reinstall 32bit Melodyne? And is that done through the main installation?