Lego Star Wars Help

[guitarfreak32]

I was playing lego star wars and was going to go into episode 1 chapter 3 when all of the sudden right before you get to the level the game turns off, i have tried several times to get into the door and the game is not working,the disc itself is brand new w/no scratches and the other episodes work perfectly fine. i have had to use a program 3D-Analyze v2.6b in order to get it to work on my laptop which doesnt have pixel shader 1.1, does anybody know how to help?