When installing the server in Ubuntu you will need to install the following:

Install Ruby
apt-get install ruby irb rdoc ruby1.8-dev

Install Rake/Rubygems
apt-get install rake rubygems 

mySQL configuration (only if connecting to a mysql database)
sudo apt-get install libmysqlclient5-dev

gem install wxruby (this is required for the gui client)

Run dradis: ruby ./script/server -p 3004
The best way to connect to the client is via ssh -X and push the xwindow back to your machine.