I am going to make an attempt at reproducing this, but I usually never get CTD doing trades with players, until last Friday, so I figured (no debug log, but I may create one if I can reproduce this)...
I selected several food and garnish items and traded them to another player, but I exceeded the items the trade window would allow. The trade was successful.
I then grabbed one of the remaining items that didn't trade. The left over items were still selected as a group, so I dragged them over to the trade window, but noticed the items I already traded were empty icon ghostly squares.
When I dropped them into the trade window and hit the trade accept button, the game crashed me to the desktop.
I hope this helps if you are still interested in troubleshooting this problem.