Around 19 minutes in, just after Ana-Lucia comes out of the armory after her first talk with "Henry", the group (Ana-Lucia, Jack, and Locke) enters the computer room. Just as she gets to the camera side of the desk, marker tape is clearly visible on the floor to position the actors properly. Pink "T" shape on the right of the table, blue strip to the left (meant to line up with Jack's left foot)
When Dr. Kim tells Sun the truth about her husband Jin's infertility being the reason for her not becoming pregnant, the subtitles read "You're husband..." instead of "Your husband..." in the first-run showing. This is corrected on the DVD release and in subsequent airings in syndication.