Sex, Losers and Videotape - S5-E20
Corrected entry: Season 5, Episode "Sex, Losers and Videotape." Grace is trying her darndest to make a sexy video to send to Leo - why? He's working on a viral outbreak in sub-saharan Africa, and he told Grace in an earlier episode "these people don't have running water." Doesn't make sense that his precious cargo of food and medicine would include a VCR, even if electricity is on hand.
Correction: Given that Grace is not all that smart and has previously shown very little understanding of how poor conditions are for Leo (in "Fagmalion Part Two: Attack of the Clones") she might not realise that he won't be able to watch the video. Alternatively, if she had, she could easily have sent him the camcorder as well, which would allow him to watch it. Either way it's not a mistake.
Shay