I`ve experienced the bug myself, but only in games edited, such as a solo or peasasnt game. The problem was posted by somebody else a while back, which also had the save edited. I do not have a solution to the problem, but if you want a 'clean' solo game and accept to start over, you can do one of three:
1) Create a normal party, drown three partymembers and play the game without editing the savegame at all..
2) Create a normal game then save immediately. Now use a savegame editor to edit only the three characters you do not want. When I play a solo I do it this way, I give the three unused characters every condition and an inventory full of mushrooms so that the solo game becomes as close to a true solo as possible. I also give my main character only 12 of the 50 bonus points at creation.
3) Edit away to your heart`s content, but test for the inventory bug at the start of the game so you can start over if it hits your main character.
Hope this helps. 
