Continuity mistake: Mulder writes Kritschgau's name on the ulnar side of the palm of Skinner's right hand. Later when Skinner is looking for Kritschgau in his apartment building, the writing is on a different part of Skinner's palm, beginning around the middle and extending diagonally towards the thumb.
Character mistake: When Kritschgau is testing Mulder's remote viewing capabilities, he tells Mulder that he is at about 5% accuracy. However, Mulder got at least two right and not enough time had passed for him to have had 40 opportunities, so his percentage of accuracy should be higher than five.
Factual error: When Mulder is visited by his mother, he definitely shows brain activity, because he is "talking" with her, however there are only flat lines on the monitor. In a similar situation in "The Sixth Extinction" episode, when Kritschgau and Skinner ask him questions and he anticipates them, the monitor shows intensive bursts.
Factual error: When Skinner is at Kritschgau's apartment building, the time stamp onscreen says it's 5:05 AM, but when Kritschgau answers his door, he says it's 6:00 in the morning. Plus it is shown to be broad daylight outside. The sun is never up that early in Washington, D.C.