Expression editor não abre no eclipse

Galera boa tarde, sou novo aqui no grupo e to com um problema que não encontrei a resolução em lugar nenhum na internet, preciso muito da ajuda de voçês.
O problema é o seguinte, estou usando o plugin do Jasper Report no eclipse porém não consigo abrir a parte do Expression Editor. estou usando o Eclipse Mars Release (4.5.1), e a versão do plugin do Jasper é a Jaspersoft Studio 6.2.0.
Quando clico no botão para abrir a Expression Editor aparece o log abaixo:

java.lang.NoClassDefFoundError: org/eclipse/xtext/service/DefaultRuntimeModule
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(Unknown Source)
at org.eclipse.osgi.internal.loader.ModuleClassLoader.defineClass(ModuleClassLoader.java:272)
at org.eclipse.osgi.internal.loader.classpath.ClasspathManager.defineClass(ClasspathManager.java:632)
at org.eclipse.osgi.internal.loader.classpath.ClasspathManager.findClassImpl(ClasspathManager.java:588)
at org.eclipse.osgi.internal.loader.classpath.ClasspathManager.findLocalClassImpl(ClasspathManager.java:540)
at org.eclipse.osgi.internal.loader.classpath.ClasspathManager.findLocalClass(ClasspathManager.java:527)
at org.eclipse.osgi.internal.loader.ModuleClassLoader.findLocalClass(ModuleClassLoader.java:324)
at org.eclipse.osgi.internal.loader.BundleLoader.findLocalClass(BundleLoader.java:327)
at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:402)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:352)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:344)
at org.eclipse.osgi.internal.loader.ModuleClassLoader.loadClass(ModuleClassLoader.java:160)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(Unknown Source)
at org.eclipse.osgi.internal.loader.ModuleClassLoader.defineClass(ModuleClassLoader.java:272)
at org.eclipse.osgi.internal.loader.classpath.ClasspathManager.defineClass(ClasspathManager.java:632)
at org.eclipse.osgi.internal.loader.classpath.ClasspathManager.findClassImpl(ClasspathManager.java:588)
at org.eclipse.osgi.internal.loader.classpath.ClasspathManager.findLocalClassImpl(ClasspathManager.java:540)
at org.eclipse.osgi.internal.loader.classpath.ClasspathManager.findLocalClass(ClasspathManager.java:527)
at org.eclipse.osgi.internal.loader.ModuleClassLoader.findLocalClass(ModuleClassLoader.java:324)
at org.eclipse.osgi.internal.loader.BundleLoader.findLocalClass(BundleLoader.java:327)
at org.eclipse.osgi.internal.loader.sources.SingleSourcePackage.loadClass(SingleSourcePackage.java:36)
at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:398)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:352)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:344)
at org.eclipse.osgi.internal.loader.ModuleClassLoader.loadClass(ModuleClassLoader.java:160)
at java.lang.ClassLoader.loadClass(Unknown Source)
at com.jaspersoft.studio.editor.jrexpressions.ui.JRExpressionsActivator.getRuntimeModule(JRExpressionsActivator.java:89)
at com.jaspersoft.studio.editor.jrexpressions.ui.JRExpressionsActivator.createInjector(JRExpressionsActivator.java:75)
at com.jaspersoft.studio.editor.jrexpressions.ui.JRExpressionsActivator.getInjector(JRExpressionsActivator.java:67)
at com.jaspersoft.studio.editor.jrexpressions.ui.support.java.JavaExpressionEditorComposite.getInjector(JavaExpressionEditorComposite.java:324)
at com.jaspersoft.studio.editor.jrexpressions.ui.support.java.JavaExpressionEditorComposite.createEditorArea(JavaExpressionEditorComposite.java:228)
at com.jaspersoft.studio.editor.jrexpressions.ui.support.java.JavaExpressionEditorComposite.(JavaExpressionEditorComposite.java:145)
at com.jaspersoft.studio.editor.jrexpressions.ui.support.java.JavaExpressionEditorSupport.createExpressionEditorComposite(JavaExpressionEditorSupport.java:45)
at com.jaspersoft.studio.property.descriptor.expression.dialog.JRExpressionPage.createControl(JRExpressionPage.java:93)
at org.eclipse.jface.wizard.Wizard.createPageControls(Wizard.java:175)
at org.eclipse.jface.wizard.WizardDialog.createPageControls(WizardDialog.java:705)
at org.eclipse.jface.wizard.WizardDialog.createContents(WizardDialog.java:597)
at org.eclipse.jface.window.Window.create(Window.java:430)
at org.eclipse.jface.dialogs.Dialog.create(Dialog.java:1096)
at org.eclipse.jface.window.Window.open(Window.java:792)
at com.jaspersoft.studio.model.text.command.EditTextFieldExpressionCommand.showDialog(EditTextFieldExpressionCommand.java:71)
at com.jaspersoft.studio.editor.gef.parts.text.TextFieldFigureEditPart$1.canExecute(TextFieldFigureEditPart.java:37)
at org.eclipse.gef.commands.CommandStack.execute(CommandStack.java:196)
at com.jaspersoft.studio.editor.gef.parts.text.TextFieldFigureEditPart.performRequest(TextFieldFigureEditPart.java:40)
at org.eclipse.gef.tools.SelectEditPartTracker.performOpen(SelectEditPartTracker.java:194)
at org.eclipse.gef.tools.SelectEditPartTracker.handleDoubleClick(SelectEditPartTracker.java:137)
at org.eclipse.gef.tools.AbstractTool.mouseDoubleClick(AbstractTool.java:1069)
at org.eclipse.gef.tools.SelectionTool.mouseDoubleClick(SelectionTool.java:527)
at org.eclipse.gef.EditDomain.mouseDoubleClick(EditDomain.java:231)
at org.eclipse.gef.ui.parts.DomainEventDispatcher.dispatchMouseDoubleClicked(DomainEventDispatcher.java:291)
at org.eclipse.draw2d.LightweightSystem$EventHandler.mouseDoubleClick(LightweightSystem.java:518)
at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:196)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4362)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1113)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4180)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3769)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$4.run(PartRenderingEngine.java:1127)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:337)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1018)
at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:156)
at org.eclipse.ui.internal.Workbench$5.run(Workbench.java:654)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:337)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:598)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:150)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:139)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:134)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:104)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:380)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:235)
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 org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:669)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:608)
at org.eclipse.equinox.launcher.Main.run(Main.java:1515)
Caused by: java.lang.ClassNotFoundException: org.eclipse.xtext.service.DefaultRuntimeModule cannot be found by com.jaspersoft.studio.editor.jrexpressions_6.2.0.final
at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:439)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:352)
at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:344)
at org.eclipse.osgi.internal.loader.ModuleClassLoader.loadClass(ModuleClassLoader.java:160)
at java.lang.ClassLoader.loadClass(Unknown Source)
… 81 more

Se alguem poder me ajudar ai galera…

vlw!