hi.. when i try to create a new class on a project i click on the finish button (the class actually gets created ) and then this error occurs :

java.lang.ClassNotFoundException: org.apache.log4j.Logger
	at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
	at org.netbeans.ProxyClassLoader.loadClass(Unknown Source)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
	at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)
Caused: java.lang.NoClassDefFoundError: org/apache/log4j/Logger
	at freemarker.log.Log4JLoggerFactory.getLogger(Log4JLoggerFactory.java:65)
	at freemarker.log.Logger.getLogger(Logger.java:255)
	at freemarker.template.utility.SecurityUtilities.<clinit>(SecurityUtilities.java:67)
	at freemarker.ext.beans.BeansWrapper.<clinit>(BeansWrapper.java:146)
	at freemarker.template.ObjectWrapper.<clinit>(ObjectWrapper.java:69)
	at freemarker.core.Configurable.<init>(Configurable.java:132)
	at freemarker.template.Configuration.<init>(Configuration.java:109)
	at freemarker.template.Configuration.<clinit>(Configuration.java:96)
	at org.netbeans.libs.freemarker.FreemarkerEngine.initFreeMarkerConfiguration(Unknown Source)
	at org.netbeans.libs.freemarker.FreemarkerEngine.eval(Unknown Source)
	at javax.script.AbstractScriptEngine.eval(AbstractScriptEngine.java:232)
	at org.netbeans.modules.templates.ScriptingCreateFromTemplateHandler.createFromTemplate(ScriptingCreateFromTemplateHandler.java:105)
	at org.openide.loaders.MultiDataObject.handleCreateFromTemplate(Unknown Source)
	at org.openide.loaders.DefaultDataObject.handleCreateFromTemplate(Unknown Source)
	at org.openide.loaders.DataObject$CreateAction.run(Unknown Source)
	at org.openide.loaders.DataObjectPool$1WrapAtomicAction.run(Unknown Source)
	at org.openide.filesystems.EventControl.runAtomicAction(Unknown Source)
	at org.openide.filesystems.FileSystem.runAtomicAction(Unknown Source)
	at org.openide.loaders.DataObjectPool.runAtomicAction(Unknown Source)
	at org.openide.loaders.DataObject.invokeAtomicAction(Unknown Source)
	at org.openide.loaders.DataObject.createFromTemplate(Unknown Source)
	at org.openide.loaders.DataObject.createFromTemplate(Unknown Source)
	at org.netbeans.modules.java.project.NewJavaFileWizardIterator.instantiate(NewJavaFileWizardIterator.java:158)
	at org.openide.loaders.TemplateWizard$InstantiatingIteratorBridge.instantiate(Unknown Source)
	at org.openide.loaders.TemplateWizard.handleInstantiate(Unknown Source)
	at org.openide.loaders.TemplateWizard.instantiateNewObjects(Unknown Source)
	at org.openide.loaders.TemplateWizardIterImpl.instantiate(Unknown Source)
	at org.openide.loaders.TemplateWizardIteratorWrapper.instantiate(Unknown Source)
	at org.openide.WizardDescriptor.callInstantiateOpen(Unknown Source)
	at org.openide.WizardDescriptor.callInstantiate(Unknown Source)
	at org.openide.WizardDescriptor.access$1600(Unknown Source)
	at org.openide.WizardDescriptor$Listener$2$1.run(Unknown Source)
	at org.openide.WizardDescriptor$Listener$2.run(Unknown Source)
	at org.openide.WizardDescriptor.lazyValidate(Unknown Source)
	at org.openide.WizardDescriptor.access$1200(Unknown Source)
	at org.openide.WizardDescriptor$Listener.actionPerformed(Unknown Source)
Caused: java.lang.reflect.InvocationTargetException
	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.openide.util.WeakListenerImpl$ProxyListener.invoke(Unknown Source)
Caused: java.lang.reflect.UndeclaredThrowableException
	at $Proxy21.actionPerformed(Unknown Source)
	at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
	at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
	at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
	at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
	at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236)
	at java.awt.Component.processMouseEvent(Component.java:6134)
	at javax.swing.JComponent.processMouseEvent(JComponent.java:3265)
	at java.awt.Component.processEvent(Component.java:5899)
	at java.awt.Container.processEvent(Container.java:2023)
	at java.awt.Component.dispatchEventImpl(Component.java:4501)
	at java.awt.Container.dispatchEventImpl(Container.java:2081)
	at java.awt.Component.dispatchEvent(Component.java:4331)
	at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4301)
	at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3965)
	at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3895)
	at java.awt.Container.dispatchEventImpl(Container.java:2067)
	at java.awt.Window.dispatchEventImpl(Window.java:2458)
	at java.awt.Component.dispatchEvent(Component.java:4331)
	at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
	at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:104)
	at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
	at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
	at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:178)
	at java.awt.Dialog$1.run(Dialog.java:1047)
	at java.awt.Dialog$3.run(Dialog.java:1099)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.awt.Dialog.show(Dialog.java:1097)
	at org.netbeans.core.windows.services.NbPresenter.superShow(Unknown Source)
	at org.netbeans.core.windows.services.NbPresenter.doShow(Unknown Source)
	at org.netbeans.core.windows.services.NbPresenter.run(Unknown Source)
	at org.netbeans.core.windows.services.NbPresenter.run(Unknown Source)
	at org.openide.util.Mutex.doEventAccess(Unknown Source)
	at org.openide.util.Mutex.readAccess(Unknown Source)
	at org.netbeans.core.windows.services.NbPresenter.show(Unknown Source)
	at java.awt.Component.show(Component.java:1447)
	at java.awt.Component.setVisible(Component.java:1400)
	at java.awt.Window.setVisible(Window.java:824)
	at java.awt.Dialog.setVisible(Dialog.java:987)
	at org.openide.loaders.TemplateWizard.instantiateImpl(Unknown Source)
	at org.openide.loaders.TemplateWizard.instantiate(Unknown Source)
	at org.netbeans.modules.project.ui.actions.NewFile.doPerform(NewFile.java:153)
	at org.netbeans.modules.project.ui.actions.NewFile.access$200(NewFile.java:84)
	at org.netbeans.modules.project.ui.actions.NewFile$PopupListener.actionPerformed(NewFile.java:348)
	at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
	at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
	at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
	at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
	at javax.swing.AbstractButton.doClick(AbstractButton.java:357)
	at javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:1225)
	at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(BasicMenuItemUI.java:1266)
	at java.awt.Component.processMouseEvent(Component.java:6134)
	at javax.swing.JComponent.processMouseEvent(JComponent.java:3265)
	at java.awt.Component.processEvent(Component.java:5899)
	at java.awt.Container.processEvent(Container.java:2023)
	at java.awt.Component.dispatchEventImpl(Component.java:4501)
	at java.awt.Container.dispatchEventImpl(Container.java:2081)
	at java.awt.Component.dispatchEvent(Component.java:4331)
	at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4301)
	at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3965)
	at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3895)
	at java.awt.Container.dispatchEventImpl(Container.java:2067)
	at java.awt.Window.dispatchEventImpl(Window.java:2458)
	at java.awt.Component.dispatchEvent(Component.java:4331)
[catch] at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
	at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:104)
	at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
	at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
	at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
	at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)