debian problems with gpg-key?

[sigi <dugongs@gmx.de>]

Hi, 

today I tried to update my debian-system, but there was a problem to 
authenticate the gpg-keys:

>---------------------------------------------------------------------<
W: GPG error: ftp://ftp.nerim.net etch Release: 
The following signatures couldn't be verified because the public key is 
not available: NO_PUBKEY 07DC563D1F41B907

W: GPG error: ftp://ftp.de.debian.org stable Release: 
The following signatures couldn't be verified because the public key is 
not available: 
NO_PUBKEY E415B2B4B5F5BBED

W: GPG error: ftp://ftp.de.debian.org testing Release: 
The following signatures couldn't be verified because the public 
key is not available: NO_PUBKEY E415B2B4B5F5BBED

[...]
>--------------------------------------------------------------------<


did they all generate new keys and I didn't receive them? 


thanks for your help,
sigi.