i've saved just before the fight with the sith assasins which appear just before you go to iziz from mandalore camp on dxun. and everytime after i've finished off the first area in front of the hangar, i get the scene where mandalore says we're going to onderon and the next thing i have to choose my party and then the bink-movie of us taking the shuttle.

 

urgh.

i found an answer on lucasart's forum.

 

BUG 3 - DXUN SITH HUNT:

 

When the Sith attack the Mandalorian camp on Dxun, make sure you kill ALL of them before you leave the area.

 

Otherwise, when you are called back later in the game, the people who are supposed to talk to you (Kaylorn, I believe) will stop talking to you in order to finish off the Sith. When the Sith are all dead, the game will refuse to advance normally.

 

NOTE: You *might* be pulled off to Onderon my Mandalore before all the Sith are killed. When you return to Dxun, just make sure you killed all of them, and all will be well.

 

But if not, when you return to Dxun later to finish Onderon, the bug will be triggered.

 

A LATER POST WROTE:

 

I've noticed something else that goes on here. Before you go to Onderon, the Sith attack the camp. After killing a few of them, Mandalore steps in and takes you to Onderon. When you return, however, there are still some Sith in the camp, most notably by the area with the Lab Station where you first spoke with Mandalore. These are the ones you MUST kill before leaving Dxun or your game will get badly screwed up when it's time to return and head to the Sith Temple/Iziz Palace. Hope that makes it a little more clear.