apt-get...not working????

[fabiand]

I just cant connect to the sites....
The answer:
Err http://ftp.rediris.es stable/contrib Release
Temporary failure resolving 'ftp.rediris.es'
Err ftp://ftp.gwdg.de unstable/non-free Release
Temporary failure resolving 'ftp.gwdg.de'
Err http://ftp.rediris.es stable/non-free Sources
Temporary failure resolving 'ftp.rediris.es'

There are a lot more messeges...is there a problem???
Thanks.