OK thanks every one for giving me good advice to consider.
Under the map window for my snare, I had the snare rim shot selected mistakenly. I changed it back to the open snare hit and suddenly my snare came back to life in for all of my AD2 kits. I remember mapping my Drum Pad to AD2 several weeks ago but I have been playing AD2 manually by using the Drum Pad only. When I tried to insert a Midi clip from an AD2 MIDIpak into my CbB Midi track, that's when I noticed I had a snare problem.
Whew, I am one happy camper now..