glad it helped
the way i see it, a person could probably have both, but really avpd is more of how you perceive yourself in situations whereas social phobia is being scared to be in the situation itself, not so much how you'd act in it. avpd makes you not want to take part in social events because you think you'll do badly or you think society will look down on you. it's very self-focused. social phobia, though, is just, i don't want anything to do with people at all, never mind what they think of me. hope that helps a little.
i had wanted to write this before but got distracted so figured the links would be better until i got the chance to reply with my own thoughts on the matter.