After installing a brand new Ubuntu 9.04 Server, add the squeezecenter repository to /etc/apt/sources.list
deb http://debian.slimdevices.com stable main
Then tell apt to reload everything:
sudo apt-get update
Now try to install squeezecenter:
sudo apt-get install squeezecenter
The following seems to be necessary to install MySQL to the machine (which I didn’t select during installation):
sudo apt-get -f install
Finally, connect to the new squeezecenter software by directing your webbrowser to port 9000 of the machine you installed the software on.
Installing SqueezeCenter on Ubuntu