Corrected entry: When Harold encounters Ms.Pascal on the MTA bus, he is so flustered that he exits a good 27 blocks from his stop. He then tries to get back on. Failing that, he proceeds back the way he came, rather than going forward to his stop.
Corrected entry: In the scene where Will Ferrell runs to the payphone in urgency to contact Emma Thompson, she is typing his actions out in narration. There is no mention on her end as to who he is calling, yet if she is the narrator and he is calling her, she should be aware of this (or at least aware of who is calling if not her). The entire scenario revolves around the fact that he is trying to call the author in desperation, yet she is genuinely shocked when she hears her own phone begin to ring.
Corrected entry: Near beginning of movie, co-worker asks Harold what 67 times 453 is. Harold couldn't concentrate because of "the voice" and quickly answered 30,351. "The voice" then says, ".despite the answer really being 31,305." Harold then corrects himself with his co-workers, telling them the "real" answer of 31,305. The answer is actually what Harold blurted out in the first place while unable to concentrate - 30,351. (Harold is supposed to be an "expert" at number problems.).