Hi

From this line:
"at XDM.main(XDM.java:9)
java.net.BindException: Address already in use
at java.net.PlainSocketImpl.socketBind(Native Method)"

it looks like there is already another instance of XDM is running.

Please check for all java process and kill them before staring XDM (use ps -A or system monitor to check any java process)