I have installed Addictive Drums. They work fine in the interface, but they just do not play in SONAR. Do I need to turn something on? You help would be appreciated.

Hi. Did you insert AD as a vsti (softsynth) in SONAR, or do you use it as a standalone (as from your desktop or the likes)? 
You should use it as a vsti inside SONAR. 
You could try to do a vst scan, under Preferences (P), File, Vst Settings. If that does not work, maybe do a vst reset, and rescan.
Best of luck.

I assume that you loaded AD2 as a Simple Instrument track.
 
1) Is Input Echo enabled? (fourth button, after Mute, Solo, and Record Enable; button should be cyan, not gray)
 
2) Is the Input set to something like a MIDI keyboard or some other triggering source?
 
3) Is the Output set to an audio output on your audio i/f or to a bus which is then routed to your i/f?

Thanks for the help.  Ken, Yes I am running it in Sonar.  Thanks Maartian good tips. I don't understand line 3 routed to my i/f?
I loaded the "All MIDI channel setup" file and all synths seem to work fine.
PEBCAK - problem exists between chair and keyboard!

Does this help?
 

 
Input is your MIDI keyboard.
Output is your audio device output (speakers/monitors/headphones).
Input Echo set to ON allows you to hear what you're playing.