Scratch Pacman

So I have dedicated more hours to creating a scratch pacman game then I would like to admit, and I am having some issues... My pacman character moves though some walls and not others. Now before you say that makes no sense allow me to elaborate. I have created a maze for the pacman character to navigate though. I have told it that when I touches the black of the walls to stop moving, and when it touches some black walls it stops... and when it touches other black walls it does not. I remember Dr. Gee talking about pleasurable frustration during his elluminate session with my class last week, and one thing is for sure I am frustrated, weather it is pleasurable, I am not so sure.