PATCH: spanish error messages updated

Hi...

I noted that the spanish error messages were not up-to-date, so I
translated a few ones missing, fixed some spelling errors, and
checked that the same expressions are being used for the same
ideas.

The patch is attached to this email, spanish peope please try it,
maybe I've missed something...

Regards,

-- 
Roberto Lumbreras
rover@lander.es | rover@etsit.upm.es | rover@debian.org & pgp 143BE391
Lander Internet, Madrid-Spain-UE; http://www.lander.es