Hi,
maybe I'm totaly wrong, but I think that's not an issue of the news reader module.
If you have a look at the generated source code of the two feeds you linked you'll see:
the one who works starts with:
<?xml version='1.0' ?>
<rss version='2.0'>
and has the "special chars" encoded like this:
Den rødgrønne regjeringens politikk trår stadig inn på kirkenes domene
The other starts with:
<?xml version="1.0" encoding="iso-8859-1"?>
And the special chars are not encoded.
Maybe this causes the pain, if your site works "per default" with utf-8 ?
Regards Bernd