I'm with Kathryn to the extent that this is part of the stage setup. In theatres "aforo" normally means the seating capacity or the house (the number of people present at a given performance), but I've never heard it used to refer to the actual physical seats, and I don't think it means that here, primarily because the seating is a front-of-house responsibility and not part of the job of the production team.

Kathryn has provided some good references to indicate that this is something to do with preparing the stage, but I don't see any evidence in them that it means stage machinery and I don't think it does. In the one that mentions "Tramoya y aforos", with no further indication of meaning, "tramoya" means stage machinery, so it is perhaps likelier that "aforos" means something else. And I think it is significant that in the first reference, the list under "aforos" consists largely of curtains.

I believe "aforos" is a variant of "foros". In the earliest Spanish proscenium theatres the "foro" was the area behing the visible stage, and it's still defined as such in the DRAE:

"foro
8. m. Teatro. Parte del escenario que está al fondo y por la que suelen acceder los intérpretes."
http://dle.rae.es/?id=IGV0NxB

But actually "foros" is also used to refer to the offstage areas to the side: the wings:

"FORO –maquinaria-
Espacio detrás o a los dados [sic, for "lados"] de la escena donde se almacenan las escenografías y se realizan montajes y cambios de escenografías entre escena y escena. El espectador no debería ver ese espacio; si lo ve, se dice que el objeto o el actor “desfora” y hay que “aforar”, es decir, colocar una pata o trasto que tape la visión del foro."
http://www.tallerdescena.com/DICCIONARIO_TECNICO_DEL_TEATRO....

And we find references to the "aforos laterales" in contexts that clearly suggest these are the wings. This is not an exclusively Colombian usage; this if from Spain:

"Término: Aletillas
Definición
Piezas, frecuentemente en forma de pliegue o añadido, que en el extremo de los telones* y de los rompimientos se doblan hacia el espectador, con el fin de cubrir los aforos laterales."
http://tesauros.mecd.es/tesauros/bienesculturales/1193717.ht...

Spain again:

"La empresa contratante se compromete a disponer de un escenario adecuado de medidas mínimas 6 X 4m con Aforos laterales"
http://www.ex3.es/_movil/contacto/bases-promocion.html

I don't think "aforos" alone means wings, because otherwise there'd be no need to specify "laterales"; this implies that there can be "aforos" that are not "laterales", which would be backstage. So I think it means offstage areas, both wings and backstage; in other words, "foros" according to the definition I cited earlier.

It seems that the word is also used to refer to the curtains covering these areas:

"Sobre el centro del escenario una pantalla blanca para teatro de sombras, enmarcada por un aforo negro tras el cual se oculta un gigante códice que se develará al final de la obra."
http://www.mincultura.gov.co/areas/artes/publicaciones/Docum...

Here's an interesting one on a puppet theatre:

"Sin aforo , frontal y lateral para permitir que el público observe el ejercicio de manipulación-oficio del titiritero."
http://titeresgranitocafecito.com.co/Obrasencartelera.htm

So "aforos" can be the offstage areas or the curtains covering those areas. In your case I think it's probably the former.


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Note added at 1 day11 hrs (2017-06-12 06:09:48 GMT) Post-grading
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Thanks, Giovanni. I've very glad you found it helpful.