Other mistake: In opening scene in the China mission society building, there is a picture of Eric Liddel hanging on the wall. Eric hadn't been born yet.
Factual error: The movie's title "The Inn Of The Sixth Happiness" is the name of the mission station that Gladys Aylward/Ingrid Bergman sets up. In reality this was called "The Inn Of The Eighth Happiness." Numerology is popular in China, where eight is regarded as a particularly auspicious number. Apparently the film company thought "sixth" had a better ring to it than "eighth." In the movie it is explained that there are six levels of happiness. This is not a Chinese belief and seems to have been invented for the movie.