Hello,
While iceweasel does allow me to download maps from the Spanish Instituto Geográfico Nacional at http://centrodedescargas.cnig.es/CentroDescargas/inicio.do epiphany fails with an ftp error such as:
Unable to load page

Problem occurred while loading the URL ftp://213.229.142.100/PUBLICACION_CNIG_DATOS_VARIOS/MTN50RASTER/0407.zip

The specified location is not mounted

Trying to download the same map using iceweasel works. Please check using this procedure:
1.-Create a user at the site and use it to log in.
2.-Choose the advanced search option (Búqueda avanzada).
3.-Choose map 407 (or any other) in the third field (Seleccione Hoja del MTN50:). Click on the "Ver listado de productos" button.
4.-Choose "MTN50 ráster" and click on the "descargar" column link.
5.-Acept the license and skip the poll.
6.-The ftp error above is shown.

This same procedure works under iceweasel.
Regards,
Luis