From the Fifth Circuit Blog, a report on the decision in United States v. Baker, No. 06-40757 (5th Cir. July 30, 2008) :
It’s not often that you see a conviction reversed because of evidentiary error, much less on plain error review. But that’s exactly what happened to one of the four child pornography counts of which Baker was convicted, all because the Government failed to lay the proper predicate for admission of the evidence it relied on to prove a distribution charge.