Jim, where've you been. We've been arguing this play for the last week!
Go to:
http://www.officialforum.com/thread/3381
However, I'm still willing to play. The following rule and case book play apply.
It is the responisbility of A1 to go around B1.
4-23-1
...Every player is entitled to a spot on the floor provided such player gets there first without illegally contacting an opponent.
10.6.1 SITUATION E: B1 attempts to steal the ball from stationary A1 who is holding the ball. B1 misses the ball and falls to the floor. In dribbling away, A1 contacts B1's leg, loses control of the ball and falls to the floor. Ruling: No infraction or foul has occurred and play continues. Unless B1 made an effort to trip or block A1,
he/she is entitled to a position on the court even if it is momentarily lying on the floor after falling down.