Collision problem

hey all, ive recently started using unity and so far so good, i like everything about it =D, ok my problem lies with collision, in my game you can control the level by rotating it left and right, using a ball as the main character that has to collect orbs. sounds confusing but if you like you can test it out here http://www.mediafire.com/?bxg6j9q7q68wxxw

ok so the collision with the balls when they touch is screwy, one ball bounces off the other in random ways. plus when the level is spinning, the ball kind of goes into the wall a bit.

just wondering if anyone has any clues (or any tips what i could do to improve) but yeah, just check it out =]

(bonus question- one more thing, if you see on the left of the level there is a blue circle.. well i want it so when the blue ball comes in contact with this cirlce, the ball goes out of play. but i do not want any other colored balls to be affected. how could i do this?

thankyou luke b