Can't install language packages

[tomi4]

Hi, I'm trying to install the Finnish language pack but Ubuntu says: "requires installation of untrusted packages". "Close" is after that the only option and no packages are installed. After googling I tried this: sudo apt-get update && sudo apt-get upgrade. This time Ubuntu first says that Some index files failed to download (in Terminal) and then the stuff about "untrusted" again.

I there a way to manually or otherwise install the package?

Thanks

[tomi4]

Installing Finnish manually:
aptitude (http://www.linux.fi/wiki/Aptitude) install openoffice.org-voikko libenchant-voikko tmispell-voikko mozvoikko

But: Failed to fetch [some files] 404 Not found [IP 130.230.54.104 80]