Continuity mistake: Dresden is missing, and Murphy comes to his office for clues. The right side window shade on the front door is pulled all the way down, and still is when Murphy leaves. But when she returns with a rescued Dresden at the end, the right door shade is halfway up, even though no one has been there to raise it.
Factual error: Talking to Dresden, Bob refers to his first grimoire (a book of spells & magic). But the closed captioner, apparently unfamiliar with the term, has rendered the line, "My first Renoir," which, though amusing, makes no sense at all in the context of the conversation. (Refers to the aired version: the error was corrected on the DVD release.)
Continuity mistake: As Harry talks to Murphy from inside the jail cell, his arms are wrapped around two bars with a third bar in the center. When the shot cuts to a wider angle, his arms are no longer draped through the bars: he's instantly standing straighter and holding onto the center bar with both hands. When it cuts back, he's in his original position again.
Deliberate mistake: Kermani finds a nitroglycerin tablet in the suspect's apartment. Because we need to see it when he holds it for the close-up, the tablet he has is much too large to be nitro. That drug is dispensed as an extremely tiny pill designed to dissolve instantly under the tongue.
Audio problem: Despite extensive overdubbing in the scene where Bob returns, the roar of helicopters can still be heard in the background. According to producers on the DVD commentary, the noise was due to firefighting aircraft overflying the sound stage during devastating L.A. brush fires in the Fall of '06.