It sounds like your dog is not sure how to handle social situations with other dogs and possibly needs some socialization or more training to teach him how to handle his stress. Some dogs need "jobs" when meeting dogs or people. I have a friend who's dog sits when it encounters other dogs or people, this gives the dog something to do and gets him past the ackward meeting.
I checked out the website you listed.
You don't say how your dog did in the classes you have taken.
A really great book you might want to look into is
http://www.clickertraining.com/store/
it gives you a postive way to help your dog through this diffcult time.
Good luck