My star wars knights of the old republic 1 wont load?

I get to the part where it auto saves but then it wont load after that i have tried many different games but it always hapens im at the part where i enter the starboard part of the ship in the first level. i have tryed to load it from the load screen and it douse load farther but it still douse not load please help. i am playing the xbox version on the 360