Daxter just bites my neighboor's kid!  

 We were walking in the hallway and the kid pass by, I was giving him the treat to distract him, but after he eats his treat he jumps to the kid and bite him in his thigh, it has 2 bites marks, not bleed but red. What should I do in this situation?

I apologize to the parents and the kid and offer if he needs to go see a doctor. They are not mad and understanding when I said sorry about it and told them that I still train my dog, and they ask for Daxter vaccination paper and I gave them that.

I've been training my dog not to bark, growl or lunge himself to people when we were out on our walk by calling his name, or say no bark or say come and give him a treat, or tug on his leash and say a firm NO if he gets too aggresive. He is getting better but this is a new thing. I thing part of that is my fault too, I should have just walk by and pass quickly instead of stop and give him a treat and ask my neighboor kid if he wants to help me train Daxter and giving him a treat.

Also when he were at pet store a girl ask if she can say hi to Daxter I said yes, she offer her hands and he sniff it, it's OK at this point, but then the girl turn to walk away and he chase her trying to bite, I pull him quickly this time.

Should I put a muzzle on him and what kind of training should I do to make Daxter more friendly to people. I don't really know his background before he end up with Ratbone, I know he don't likes small kids but should be OK with teens.

Help please! Thanks!

Daxter is a Ratbone dog?  If so he's neutered.  Have you joined the Ratbone Extra chat site for adopters and volunteers?  You can get lots of good advice and help on there.

But for right now - please don't let him near any children.  Until you get his behavior under control you cannot risk him biting children - besides the fact you could be sued it could be a death sentence for Daxter!  And "agressive" dog who's bitten children - many shelters and vets would advise them being euthanized.  So please - for Daxter's sake, don't let him near children right now.

And yes, you should have kept his attention on you and walked briskly past the neighbor and child.  And since he's exhibiting problems you shouldn't have allowed the child at the pet store to pet him. 

Nora can help you with training and you can also get a trainer or behaviorist to help you with him.  Also, on Ratbone Extra there is a dog behaviorist who's a RBR volunteer and she can give you some advice.  it's RatboneExtra@yahoogroups.com .

This is a good place to start when looking for a trainer: 
www.apdt.com/

It would probably be a good idea to look for a trainer.  They can help you determine the cause of the biting (It could be fear, dominance, lack of socialization) etc...   Once they determine the cause, they can help you develop a behavior modification plan.  I'd muzzle him while you are out.  What about one of those basket muzzles?  The kind like they use on greyhounds? I had one for my greyhound, she came off the track with it.  It was very handy since she tended to display some aggression around other female dogs.  For greyhounds this type of muzzle is something they are quite used to, but I imagine you could find them in any size.    You can still feed treats to him through that and he can still drink water with it on.

   Only treat for relaxed behavior around children or whomever he is demonstrating this behavior to.  Then you are rewarding relaxed behavior.   Don't treat when he is acting crazy in an attempt to distract him.  Like someone else mentioned, this is only reinforcing the behavior.   Increase distance from those things he is uncomfortable with.   I wouldn't let people approach him until you can get a trainer to help you out.  The muzzle should signal to people to keep their distance.  But you may have to explain to well-meaning children to stay at a distance.  This is for the dog's safety as well as the children's. 

"Also when he were at pet store a girl ask if she can say hi to Daxter I said yes, she offer her hands and he sniff it, it's OK at this point, but then the girl turn to walk away and he chase her trying to bite, I pull him quickly this time."

From your first post about the girl at the pet store I would not let the neighbor kid around Daxter until you consult with the trainer.  JMO but the trainer/behaviorist will better understand how to handle this safely.