I know the last comment is a month old now, but google is still driving people
here for an answer. I found this on the web:
http://www.namhuy.net/3116/how-to-fix-gpg-error-no_pubkey-in-ubuntu.html
$ sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys
40976EAF437D05B5
Run this command f
It actually says in the man page that from the command line you have to
use brackets around a IPv6 address. Too bad the gui doesn't seem to
follow this logic, even though the tooltip for a connection lists the
IPv6 address in brackets.
>From man vinagre
[server][::port|:display]
