Menu Active option

you don't have to do this ... just write the styles in the theme file like explained.

but I see a problem probably due to the fact that you are using some alias in your menu structure ? the active class is not given to the item

use this css code instead
#accordeonck125 a.isactive {color: red;}

I change the code for that, but the problem persists.

I attached a image

look at here, it works
www.st-ingenieriaforense.com/nuevaST/ind...ia-de-la-informacion

Exactly. In "Servicios" work well, but in the other not. I check all the option of the modules and is exactly equal. I do not understand

this is not a problem from the module but from your menu structure, these classes are the same as the native joomla menu module. You can make the test by replacing the accordeon menu by a mod_menu and see if you get the active class