Factual error: Laura Ingalls Wilder was born in 1867. Ralph Waldo Emerson died in 1882, which means she was at the maximum 15-16 years old (and already married) in order to meet him IF he were to appear in 1882 which is not possible because: The problems with his memory had become embarrassing to Emerson, and he ceased his public appearances by 1879 (according to wikipedia).
Factual error: There is no physical way that Steve Austin could perform most of his superhuman feats of strength in the ABC television series, due to the fact that they simply replaced his arm and legs, but didn't rebuild or reinforce the rest of his skeleton and muscles to handle the physical loads. Interestingly, author Martin Caidin (creator of Steve Austin in his novel, "Cyborg") actually did describe an incredibly complex whole-body rebuild that included vertebral reinforcement and ribcage and pelvis replacement, which was far more scientifically-accurate than the subsequent ABC television interpretation. ABC only accepted the series on the condition that it was less technical for their audience.
Uniform Day - S6-E17
Factual error: It is Uniform Day where they all have to wear their uniforms. The badges they all wear are those of patrolmen. The problem is that they are detectives and the NYPD has detective badges, which are distinctly different looking.
The Countess - S1-E4
Factual error: Two cops (the bowtie guy that cuffs Rockford and the one that watches him being taken away from his trailer) report to HQ saying that the protagonist is a suspect for a 157, to which Rockford reacts saying he did not murder anyone (and it is in fact what he is accused of). But homicide is in CA police code 187, not 157. A 157 is an entirely different felony. (00:21:00)