Special characters not displaying since 2 days ago.

Hello community,

I have been playing with a WoW client version in Spanish. The 3.3.5a. But since two days ago, my special characters such as "ñ" "Í" "ó" and so on will show as seen in the picture below.

http://imgur.com/a/Vvpma

As you can see, the quest log has the errors. BUT the zone text under the minimap does not. It started happening two days ago, before that I always saw it perfectly.
Another important point is that a friend that is playing here aswell with the same client encountered the same issue the same day, by the same time.

And no, he does not use almost any addon apart from Recount and Grid.

Any ideas on how to solve this? Is this problem server-side?

Thank you.