Essentially, the plot-critical quest "Ebon Hawk ID Signature" is broken. Everything seems to work up until the cutscene that plays with the Ebon Hawk taking off... only instead of the story advancing, the game plays an incorrect cutscene from earlier in the story (some Duros(?) bounty hunters in the cantina, discussing the Exchange' trap). After the wrong cutscene plays, the party respawns in front of the Ebon Hawk--still on Nar Shaddaa--and the events with the droid repair shop are "reset."
So, I can go back to the droid guy and request a new ID signature, but the quest is no longer active, and I'm unable to obtain a new ID signature because I no longer have the blank ID card. And, of course, there's no way to leave the planet because the Ebon Hawk demands a new ID signature.
I'm playing the game with the Sith Lords Restoration patch... and even then I've encountered dozens of bugs. I've always heard people praise KOTOR2 effusively, but this is the second game-breaking bug I've found and if I can't find a way to get around it I'm just gonna give up entirely. So, please--help me out, would ya'?
I'm thinking that I might be able to fix it by changing some of the global variables with the save editor--like the thing causing this might be that the wrong cutscene that plays might be assigned a "0" instead of a "1" or something--I don't know. I'm really desperate for help here... evidently, no one else in the whole Internet has had this problem, going by Google search results.