Have you tried handing items to other npcs? I think you'll get the same error. When I sourced in the updated db.sql file that Drawde posted in his World Data 1.1 final (before he posted the updated, fixed version -- haven't tried that file), I got a bunch of errors when I sourced it in and subsequently lots of errors in the reloaddb.sql. I think it was the errors that caused the problem.
Try and see if you do get that bug when you try and hand npc's anything (or pc's -- when I had the bug I only noticed it with PC's... never tried to give anything to an NPC). If you do, then what I did to get it to work, and source without any/minimal errors, was first source in the basic 4.3 DB.sql, then source in Drawde's updatedb.sql (forget the exact filename), then sourced in reloaddb.sql, etc. Got no errors, and found that the "ERROR: Getitem()..." bug disappeared, along with a few others (backpack errors).
I haven't looked at or tried any quests yet, so I can't say if there are any problems with that, just noticed your error was the same as mine so thought it could be the same thing that happened with me.
Hope that helps. If anything was too confusing let me know and I'll try to explain better.
