Wicket Exception

I am building a simple web application in wickets and am getting the following exception

og4j:WARN No appenders could be found for logger (org.mortbay.log).
log4j:WARN Please initialize the log4j system properly.
>>> STARTING EMBEDDED JETTY SERVER, PRESS ANY KEY TO STOP
********************************************************************
*** WARNING: Wicket is running in DEVELOPMENT mode.              ***
***                               ^^^^^^^^^^^                    ***
*** Do NOT deploy to your live server(s) without changing this.  ***
*** See Application#getConfigurationType() for more information. ***
********************************************************************
java.net.BindException: Address already in use: JVM_Bind
      at java.net.PlainSocketImpl.socketBind(Native Method)
      at java.net.PlainSocketImpl.bind(Unknown Source)
      at java.net.ServerSocket.bind(Unknown Source)
      at java.net.ServerSocket.<init>(Unknown Source)
      at java.net.ServerSocket.<init>(Unknown Source)
      at org.mortbay.jetty.bio.SocketConnector.newServerSocket(SocketConnector.java:78)
      at org.mortbay.jetty.bio.SocketConnector.open(SocketConnector.java:72)
      at org.mortbay.jetty.AbstractConnector.doStart(AbstractConnector.java:252)
      at org.mortbay.jetty.bio.SocketConnector.doStart(SocketConnector.java:145)
      at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:40)
      at org.mortbay.jetty.Server.doStart(Server.java:231)
      at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:40)
      at edu.tamhsc.tuition_waiver.Start.main(Start.java:35)

Any ideas on what I might be doing wrong.

Thanks