The fundamental attribution error is an important psychological concept that is defined as the mistake of attributing personality as the sole cause of observed behavior while overlooking the possibility that situational factors may be the actual attributable cause(s). In other words, we err in thinking that a persona's personality is the sole explanation of observable behavior when in fact situations may be the determining factor and not personality after all.
In Mad Hot Ballroom, the individuals who might demonstrate an attribution error are the students, the teachers and principals, the dance instructors, the director/questioner, and the camera. At first analysis, I don't see where this error might be represented, but let's examine possibilities together.
The camera is always an active player in any film, especially a documentary in which the distanced objectivity of the camera is traded for the documenter's subjective perspective. This camera kept tight shots of the students on sidewalks, in parks, and in homes in keeping with the director's objective to tell a dance story. It might thus be argued that the camera was guilty of presenting personality above situation as the sole attributable factor for students' behaviors. This same analysis is applicable to the director, though the defensibility of these arguments is debatable.
The director has stated publicly that she did not pursue the students' backgrounds because the socio-economic stories of New York's inner city schools has been told. This might be perceived as resulting in an attribution error because it might be concluded that she then erred in attributing their personalities as the sole factors in their behavior during dance preparation and competition. While this might be analyzed this way, I think it is less than defensible to describe a reasoned decision to tell a specific story as an attribution error.
The dance instructors enter a situation for a brief time with a specific, time sensitive goal. Their only concern is the personality of the young dancers before them, especially since they want to tap those personalities to train emotive, expressive dancers. Aside from the fact that this is a valid, defensible active choice, this might be said to represent the attribution error. The teachers and principals, on the other hand, don't demonstrate this error at all as they are very familiar and conversant with the students' various situations.
It might be said the students view the dance instructors and dance judges based on perceived personality alone without taking situation into account as a factor in their behavior. Yet this seems superfluous as the students and instructors developed a strong bond showing the students didn't question the behavior they saw, rather grasped the essential nature of what they perceived in the instructors' behavior. Nonetheless, since the students didn't consider situation at all in relation to the instructors, this might be called an instance of the attribution error.
If the argument must be made that someone in the film demonstrated the fundamental attribution error, the students, camera, and director are the most reasonable candidates. The arguments may be hard to defend, though, because their approaches were realistic (the students) or based on well reasoned and tightly aimed choices and objectives (the director, camera).