I have no experience with Mugshot, but I'll throw out some ideas.
Why not just install from the source code? It's available at
http://download.mugshot.org/client/sources/linux/
I took a peek at the Gentoo ebuild for this, and these are the dependencies you'll need to satisfy... gtk+-2.6, dbus, loudmouth, gconf, and curl. In addition, loudmouth has its own set of dependencies. You probably have at least gtk already installed. Maybe you should try
www.slacky.it or linuxpackages.net to get packages for the rest.
Hope this helps.