Problem with hittest - object solidity?

Hi,

I am quite new to flash, and have started making break out, to learn some game programming aspects and knowledge, i have a ball pinging around the screen, the only problem at the moment is when the ball hits the top or bottom of a block it pings off in the opposite coordinates, but on the side of the object it goes through it awkwardly instead of pinging:-

                       ________
  • here goes thru * |_______| *

Anyone come across this before?