root
apt-get update

problem is :

W: GPG error: ftp://ftp.mozilla.org chinook Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 667387BFFF445C24
W: Conflicting distribution: http://repository.maemo.org fremantle-1.3 Release (expected fremantle-1.3 but got )
W: GPG error: https://downloads.maemo.nokia.com ./ Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY ADB4438160A655EF
W: GPG error: http://moff.mozilla.com fremantle Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 667387BFFF445C24
W: You may want to run apt-get update to correct these problems