You should be able to find these components under
C:\Program Files\Cakewalk\Shared Utilities\Internal. Look for items called PCS-BusCM.dll (PC4K Bus Comp) and PCS-NukeCM.dll (PC76 Comp). If you don't see these here, it's best to just run the SONAR installer again.
If you do see them here, go into SONAR and go to Edit > Preferences > File > VST Settings.
Click Reset... (just to be on the safe side). Click Yes. If a scan does not begin automatically, click
Scan. That should get you going :)