Having just gone to dependency hell and back getting this to work I though I would point out what for me was not obvious. I read and confirmed that if you get one frontend to work the rest will as well. The problem is not the webui frontend, but rtorrent itself. I relied very heavily on three guides:
Rather than rewrite new guide I will explain what I changed. The problem I faced with precomplied version from the distro's repositiories was using the older version of xml-rpc-c. At this point rtgui did work, but rutorrent not well. You must have rtorrent complied with the same version libraries as your installed xml-rpc and a least version 1.06, but rutorrent needs 1.11 or newer.
I used the complile directions for the wtorrent link above. with a minor change. If you have not used subversion, it is the greatest thing for getting current source code files. There is a subversion checkout for xml-rpc-c. Follow the directions for compiling xmlrpc-c except replace the first 2 lines with the following that I derived from the xmlrpc sourceforge page:
svn checkout $REPOS xmlrpc-c
At the time of this post the stable version number is 1.16. I had to also grab from the distro's experimental section and install the following files to match the same version number:
It is very important in this case that all these files are version 1.16. The rest of the directions complied without error after adding the lib32ncurses5-dev library. Also not so obvious is the .rtorrent.rc file that is required for rtorrent to run. I had to comment out the line for the log file since it seems this version does not support logging. I modified it so that the .rc file and the torrent directories were all in my running user home folder and the settings were matched to my internet connection.
The rest of the rtgui directions work perfectly. Before I complied the precompiled version 1.06 of xml-rpc-c actually worked with rtgui but rutorrent complained and files larger than 4GB showed incorrect file sizes. Once you have rtorrent updated then any of the frontends should work. Both rtgui and rutorrent can display the same torrent activity at the same time.
I installed this on a headless server in the Netherlands running debian lenny. I could not get it to run at all on a test box at home running ubuntu hardy. The problem is hardy is already too old. These pointers should work on any version of linux.
The only thing left is to have rtorrent run as a server and add a username/password login. I know there should be an easy way to add login if some kind soul could point me in the right direction.