George, if you will look at http://www.nps.gov/history/history/online_books/rthg/fore.htm you might conclude it was Jesse Jackson Jr. and the year was 2000. Now, if you can find a way to get back to the year 2000 board posts, you may find it?

This pins it down a little more closely to May 2000

http://findarticles.com/p/articles/mi_m1355/is_25_97/ai_62590958/

Google "National Park Service" "Jesse Jackson" and "Slavery" and you will get a bunch of hits

Hope this helps you find the entry point into Jim's archives.

Dennis