To anyone who crashes to mainscreen which then subsequently locks when trying to enter a new area. I had this problem on Paragus after finishing the Harbinger and trying to get back to the Ebon.
Everytime I went through the lift door up the ramps (where t3 was earlier) instead of the next section loading I would get chucked to main kotor screen where it would freeze on me.
I fixed the problem by firstly deleting my autosave and unticking the autosave option.Then after loading back to my very last save, (which was just after Kreia and Sion fight) I deleted every other save I had.
Then, returning to windows with the game still running in the backround, I went into SWkotOR2 and then deleted everything in the gameinprogress file and currentgame file respectivley. Then I played on with my fingers and toes crossed. It worked. I dont know how or why, but it worked. I walked into the lift and it loaded up not a problem.
Alls well that ends well? No. Apparently T3 is supposed to be in the tunnel where he then joins the team. Not in my tunnel. I thought it was wierd when Atton for no apparent reason said something about T3 lying abandoned just over yonder. And now I cant open the other door without him. I think there doing this on purpose...!
Anyway hope it helps. If anyone knows how to make a missing character reappear post away!