>>>>> Katsumi Yamaoka wrote:
> Anyway we will need time to fix this problem (see `w3m-ucs-to-char'
> provided in w3m-ems.el and w3m-xmas.el and `w3m-decode-entities' in
> w3m.el.)

I made a patch for mm-util.el and mm-url.el, however I'm not quite
sure it works in your Emacs environment (locale?, language?, ...).
So could you try loading the attached file and reading the nnrss
group in question?  If it works, I'll add them to No Gnus.