ora cerco di aggiornare anche con APT.
Mi ricordate come risolvo questo?

Checking GPG signatures...
Unsigned /var/cache/apt/archives/docbook%5f4_4.3-0.1_noarch.rpm: sha1 md5 OK
Unsigned /var/cache/apt/archives/synaptic_0.48.2-rb.suse091.1_i586.rpm: sha1 md5 OK
E: Error(s) while checking package signatures:
2 unsigned package(s)
0 package(s) with unknown signatures
0 package(s) with illegal/corrupted signatures