مشكلة في الديجي شات او الجافا

at com.diginet.digichat.server.ChatServer.<init>(Unknown Source)
at com.diginet.digichat.server.ChatServer.main(Unknown Source)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.zerog.lax.LAX.launch(Unknown Source)
at com.zerog.lax.LAX.main(Unknown Source)

java.lang.NullPointerException

at java/lang/Class.forName
at com/zerog/lax/LAX.launch
at com/zerog/lax/LAX.main

java.lang.NoClassDefFoundError