[eluser]Aken[/eluser]
Does your route actually say news, or did you translate it to noticias?
Also, a small fix to what I said about that route - you don't need the parentheses if you aren't going to reuse that segment.
Code:
$route['noticias/:num'] = 'news';
You have something small wrong somewhere. It might be worth starting from scratch and add code until you find where the problem is.