A couple of suggestions/thoughts…
I am assuming you can hear the grooves when you click on them…
- Make sure you have updated your version of EZD to the latest available from Toontrack.
- Try loading the grooves to a different type of CB track. Meaning if trying to drag into a midi track, try dragging into an instrument track (or vise-versa).
- Make sure you are dragging the groove from the “correct” area on the groove itself.
Good luck and let us know how you sort this out (if you ever do). 
Regards 