Uwe Brauer wrote:

> I just used the tdenetworkmanager for the wired net and everything is
> fine, I think I will forget the systemsettings for the network.

Yes it is better to not have anything in the /etc/network/interfaces file
I had the same problem when I started using tde network manager. After some
discussions I was convinced it is not a but.
Also wireless works for me fine.

regards