ergophobe - 6:04 pm on Jan 12, 2012 (gmt 0)
Moot question now. I simply started with a clean slate, imported data in the smallest chunks possible (i.e. clusters of related tables), until I had everything I wanted in the new site. Never did find out what setting was causing it, since I imported almost the entire DB.
Pain in the butt. I could have done it in one fifth the time, but I did really want to understand the cause. I think you understand this coopster.