using jepp in knime application.

i want to use jepp.
jepp is python enveloper module in java.

so i downloaded jep.jar file in jepp site.
and I added jep.jar external library files. (using http://tech.knime.org/developer/faq#q19)
but when i started knime,
the error is occuring… plz, help me.

2010-06-23 22:45:04,343 DEBUG main CreateNodeCommand : Node cannot be created.
java.lang.NoClassDefFoundError: jep/JepException
at test.TestNodeFactory.createNodeModel(TestNodeFactory.java:21)
at test.TestNodeFactory.createNodeModel(TestNodeFactory.java:1)
at org.knime.core.node.NodeFactory.callCreateNodeModel(NodeFactory.java:640)
at org.knime.core.node.Node.(Node.java:229)
at org.knime.core.node.workflow.WorkflowManager.createAndAddNode(WorkflowManager.java:351)
at org.knime.workbench.editor2.commands.CreateNodeCommand.execute(CreateNodeCommand.java:111)
at org.eclipse.gef.commands.CommandStack.execute(CommandStack.java:170)
at org.knime.workbench.editor2.NodeTemplateDropTargetListener2.drop(NodeTemplateDropTargetListener2.java:182)
at org.eclipse.jface.util.DelegatingDropAdapter$3.run(DelegatingDropAdapter.java:211)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:37)
at org.eclipse.core.runtime.Platform.run(Platform.java:880)
at org.eclipse.ui.internal.JFaceUtil$1.run(JFaceUtil.java:48)
at org.eclipse.jface.util.SafeRunnable.run(SafeRunnable.java:175)
at org.eclipse.jface.util.DelegatingDropAdapter.drop(DelegatingDropAdapter.java:209)
at org.eclipse.swt.dnd.DNDListener.handleEvent(DNDListener.java:90)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1003)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1027)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1012)
at org.eclipse.swt.widgets.Widget.notifyListeners(Widget.java:770)
at org.eclipse.swt.dnd.DropTarget.Drop(DropTarget.java:455)
at org.eclipse.swt.dnd.DropTarget$3.method6(DropTarget.java:257)
at org.eclipse.swt.internal.ole.win32.COMObject.callback6(COMObject.java:119)
at org.eclipse.swt.internal.ole.win32.COM.DoDragDrop(Native Method)
at org.eclipse.swt.dnd.DragSource.drag(DragSource.java:362)
at org.eclipse.swt.dnd.DragSource.access$0(DragSource.java:288)
at org.eclipse.swt.dnd.DragSource$1.handleEvent(DragSource.java:171)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1003)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:3823)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3422)
at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2384)
at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2348)
at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2200)
at org.eclipse.ui.internal.Workbench$5.run(Workbench.java:495)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:288)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:490)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
at org.knime.product.rcp.KNIMEApplication.start(KNIMEApplication.java:112)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:193)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:386)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:549)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:504)
at org.eclipse.equinox.launcher.Main.run(Main.java:1236)
at org.eclipse.equinox.launcher.Main.main(Main.java:1212)
Caused by: java.lang.ClassNotFoundException: jep.JepException
at org.eclipse.osgi.framework.internal.core.BundleLoader.findClassInternal(BundleLoader.java:483)
at org.eclipse.osgi.framework.internal.core.BundleLoader.findClass(BundleLoader.java:399)
at org.eclipse.osgi.framework.internal.core.BundleLoader.findClass(BundleLoader.java:387)
at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.loadClass(DefaultClassLoader.java:87)
at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)
… 52 more
2010-06-23 22:45:05,140 DEBUG main NodeContainer : Setting dirty flag on KNIME_project 0:0
2010-06-23 22:45:05,140 DEBUG KNIME-Workflow-Notifier KnimeResourceNavigator : ROOT’s workflow has changed WORKFLOW_DIRTY
2010-06-23 22:45:05,140 DEBUG main WorkflowRootEditPart : WorkflowRoot: command stack changed
2010-06-23 22:45:05,140 DEBUG KNIME-Workflow-Notifier WorkflowEditor : Workflow event triggered: WorkflowEvent [type=WORKFLOW_DIRTY;node=0:0;old=null;new=null;timestamp=Jun 23, 2010 10:45:05 PM]
2010-06-23 22:45:05,140 DEBUG KNIME-Workflow-Notifier WorkflowRootEditPart : WorkflowRoot: workflow changed, refreshing children/connections…
2010-06-23 22:45:06,218 DEBUG main WorkflowRootEditPart : WorkflowRootEditPart deactivated
2010-06-23 22:45:06,218 DEBUG main ProjectWorkflowMap : unregistering org.knime.workbench.editor2.WorkflowEditor@1cc0a0f from /KNIME_project. 0 left.
2010-06-23 22:45:06,218 DEBUG main ProjectWorkflowMap : Removing “/KNIME_project” from project map (0 remaining)
2010-06-23 22:45:06,218 DEBUG main KnimeResourceNavigator : ROOT’s workflow has changed NODE_REMOVED
2010-06-23 22:45:06,218 DEBUG main KnimeResourceNavigator : Workflow KNIME_project 0:0 removed
2010-06-23 22:45:06,218 DEBUG main NodeContainer : KNIME_project 0:0 has new state: EXECUTED
2010-06-23 22:45:06,218 DEBUG main NodeContainer : Workflow Manager 0 has new state: IDLE
2010-06-23 22:45:06,218 DEBUG main WorkflowEditor : Disposing editor…