Emily, I'm sorry to hear about this situation. I feel for you and the gentleman; whatever the dog did or did not do, it was perceived as aggressive and that's really all that matters.

As a dog owner, I'm very nervous about something like this happening. I am training my dog for the Canine Good Citizen certification. It's difficult with him because he's a rescue from an abusive situation and there's alot of doggie baggage to get through. He dislikes most children because he was abused by them, but if he ever went after a kid, that would be the end of him regardless of the reasons, history, or even if it wasn't really aggressive. It's all about perception.

When a dog jumps, the best thing to do is simply turn away and walk away. Eventually the dog will figure out that jumping is not going to result in attention. This is what you should do for training. Especially with small dogs, people tend to encourage jumping without realizing it because they bend down and talk in baby-dog talk (I can't stand that, but it happens). When you get home, don't reward the jumping by bending down and petting and talking to the dog. Turn away and ignore the dog until he stops jumping and calms down. Then approach the dog and praise him, but only if he remains unjumpy.

Best wishes for getting this sorted out, Emily!