On betrayal over bespin the melenium falcon won't open. I have all minikits..

The same thing happened to me once. What I did was I went back through the level, and I killed off the rest of the Stormtroopers. Or you can go around to the back of the Millenium Falcon to see if one got stuck back there. Other than that...

Find and kill all enemmies
P.s.you can't have all things if you havent beaten it

in free play mode, go through the level without collecting much. at the end, fight the stormtroopers only at the area where the millinium falcon door is, then a scene will show the door opening. of course, go back and collect everything before exiting the level. in case if you don't know what level i'm talking about, it's Betrayal over bespin

There are no storm troopers left alive in the level and none around the millennium falcon and the doors still wont open explain that one

I think I FINALLY figured it out. I've been having the same problem, and I've tried a whole bunch of times and I finally got a success.

Have you been using a ghost character? This whole time I've been using Ghost Anakin since he's basically invincible. I picked Lando as my character and went straight to the end and killed all the Stormtroopers, and the door finally opened! I think if you use a ghost character (or possible invincibility, though I haven't tried that yet), it'll get glitchy.