http://www.lucasforums.com/showthread.php?t=163778)
For deeper troubleshooting of KSE problems, you can peform further diagnostics using a kse.log file by following these steps.
1. Create a file called kse.log and put in the same directory as KSE.
2. Launch KSE and try to recreate the error.
3. Close KSE.
4. Read the contents of kse.log in Notepad. You may be able to diagnose the problem yourself from the last couple entries in the log. If not you can email the log file to me at the email address in kse-readme.txt.Typically that error is caused by either a corrupt savegame, a corrupt override item, or a missing override item.
I should've put more error trapping in place a long time ago. :(