Hello, I'm new to both the Linux/Unix and TuxGuitar communities, and as I was trying to install TuxGuitar on my Ubuntu Eee PC, I got this error message:
W: GPG error: http://download.tuxfamily.org p701 Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 2042B4BAF2BCFBF8
You have some problem on your apt repositories ( as your error say NO_PUBJEY )
you should ask it on ubuntu forums ( we are not ubuntu developers, so we can't give you enougth help )
anyway, "http://download.tuxfamily.org" don't seems to be an official ubuntu repository..
did you add it manually ?? you could see at it's official page if there is a key to access it.