butuh bantuan lg gan

ane mo ganti tampilan grub tp pas add ppa kok error ya..
klo add lwt CLI

Cannot access PPA ([url]https://launchpad.net/api/1.0/~n-muench/+archive/burg[/url]) to get PPA information, please check your internet connection.

pdhal internet fine,instal yg lain lancar.

klo add lgsg lwt software source d GUI, muncul error jg pas update,pdhl other source sdh d centang.

W: GPG error: http://ppa.launchpad.net quantal Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY A6804EA8EAE0D85C

itu mksd pubkey apa y, solusinya gmn