The server is required to use MultiRemote. The mobile application doesn't work alone. There is nothing to install. Simply extract the files and run the executable (.jar).
Warning ! This server is a Java application. You need to have the Java Runtime Environment (JRE). You can download it at the Java website : http://www.java.com/fr/download/.
If you don't find my app in the market, you can download it here : Multiremote Client for android