New to Java

Hi

I?m currently working on a program which uses a rule based expert system. I am using eclipse with the expert system shell drools (3.0).

The program works fine when I run it in eclipse but when I try to export the program as a jar file it does not seem to work. I did cmd java -jar to find out what's going wrong and it gives me the following error messages:

Exception in thread "main" java.lang.NoClassDefFoundError: org/drools/RuleBase
at com.sample.GUI.<init>(GUI.java:34)
at com.sample.GUI.main(GUI.java:41)

and also:

Exception in thread "AWT-EventQueue-0" java.lang.NoClassDefFoundError: org/drool
s/RuleBase
at com.sample.beakAndBill.actionPerformed(beakAndBill.java:64)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.JToggleButton$ToggleButtonModel.setPressed(Unknown Source
)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Sour
ce)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)

can anyone help me with this problem. I know that it?s probably missing the drools classes and if that is the case can anyone tell me how to add the classes.

Thanks in advance.